|
Fair Value Measurements (Details) (USD $)
In Millions, unless otherwise specified |
May 31, 2014
|
May 31, 2013
|
||||
|---|---|---|---|---|---|---|
| Available-for-sale securities: | ||||||
| Available-for-sale securities | $ 3,391.4 | $ 3,691.4 | ||||
|
Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 65.8 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 3,391.4 | 3,691.4 | ||||
| Other | 12.3 | 10.7 | ||||
| Liabilities: | ||||||
| Other long-term liabilities | 12.3 | 10.7 | ||||
|
Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 6.0 | |||||
|
General obligation municipal bonds [Member]
|
||||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 1,628.5 | 1,456.8 | ||||
|
General obligation municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 10.9 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 1,628.5 | 1,456.8 | ||||
|
Pre-refunded municipal bonds [Member]
|
||||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 142.8 | [1] | 203.9 | [1] | ||
|
Pre-refunded municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 31.2 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 142.8 | 203.9 | ||||
|
Revenue municipal bonds [Member]
|
||||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 867.8 | 754.0 | ||||
|
Revenue municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 17.7 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 867.8 | 754.0 | ||||
|
Variable Rate Demand Obligation [Member]
|
||||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 752.3 | 1,276.7 | ||||
|
Variable Rate Demand Obligation [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 752.3 | 1,276.7 | ||||
|
Quoted prices in active markets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 0 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 0 | 0 | ||||
| Other | 12.3 | 10.7 | ||||
| Liabilities: | ||||||
| Other long-term liabilities | 12.3 | 10.7 | ||||
|
Quoted prices in active markets (Level 1) [Member] | Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 0 | |||||
|
Quoted prices in active markets (Level 1) [Member] | General obligation municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 0 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 0 | 0 | ||||
|
Quoted prices in active markets (Level 1) [Member] | Pre-refunded municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 0 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 0 | 0 | ||||
|
Quoted prices in active markets (Level 1) [Member] | Revenue municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 0 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 0 | 0 | ||||
|
Quoted prices in active markets (Level 1) [Member] | Variable Rate Demand Obligation [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 0 | 0 | ||||
|
Significant other observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 65.8 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 3,391.4 | 3,691.4 | ||||
| Other | 0 | 0 | ||||
| Liabilities: | ||||||
| Other long-term liabilities | 0 | 0 | ||||
|
Significant other observable Inputs (Level 2) [Member] | Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 6.0 | |||||
|
Significant other observable Inputs (Level 2) [Member] | General obligation municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 10.9 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 1,628.5 | 1,456.8 | ||||
|
Significant other observable Inputs (Level 2) [Member] | Pre-refunded municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 31.2 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 142.8 | 203.9 | ||||
|
Significant other observable Inputs (Level 2) [Member] | Revenue municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 17.7 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 867.8 | 754.0 | ||||
|
Significant other observable Inputs (Level 2) [Member] | Variable Rate Demand Obligation [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 752.3 | 1,276.7 | ||||
|
Significant unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 0 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 0 | 0 | ||||
| Other | 0 | 0 | ||||
| Liabilities: | ||||||
| Other long-term liabilities | 0 | 0 | ||||
|
Significant unobservable Inputs (Level 3) [Member] | Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 0 | |||||
|
Significant unobservable Inputs (Level 3) [Member] | General obligation municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 0 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 0 | 0 | ||||
|
Significant unobservable Inputs (Level 3) [Member] | Pre-refunded municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 0 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 0 | 0 | ||||
|
Significant unobservable Inputs (Level 3) [Member] | Revenue municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Assets: | ||||||
| Cash Equivalents | 0 | |||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | 0 | 0 | ||||
|
Significant unobservable Inputs (Level 3) [Member] | Variable Rate Demand Obligation [Member] | Fair Value, Measurements, Recurring [Member]
|
||||||
| Available-for-sale securities: | ||||||
| Available-for-sale securities | $ 0 | $ 0 | ||||
|
||||||