Quarterly report pursuant to Section 13 or 15(d)

Short-term Financing (Narrative) (Details)

v3.19.1
Short-term Financing (Narrative) (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Mar. 13, 2019
Feb. 28, 2019
Feb. 28, 2018
Feb. 28, 2019
Feb. 28, 2018
May 31, 2018
Subsequent Event [Member]            
Financing [Line Items]            
Senior notes $ 800.0          
Series A Senior Notes [Member] | Subsequent Event [Member]            
Financing [Line Items]            
Senior notes $ 400.0          
Interest rate 4.07%          
Maturity date Mar. 13, 2026          
Series B Senior Notes [Member] | Subsequent Event [Member]            
Financing [Line Items]            
Senior notes $ 400.0          
Interest rate 4.25%          
Maturity date Mar. 13, 2029          
Revolving Credit Facility [Member] | JPM $1 Billion Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member]            
Financing [Line Items]            
Amounts outstanding   $ 400.0   $ 400.0   $ 0.0
Amount borrowed   $ 400.0 $ 200.0 $ 483.0 $ 700.0  
Number of days borrowed   71 days 2 days 81 days 21 days  
Weighted-average interest rate   3.48% 4.25% 3.66% 4.24%  
Weighted-average amount borrowed   $ 400.0 $ 125.0 $ 385.9 $ 311.9  
Revolving Credit Facility [Member] | JPM $1 Billion Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Three Days [Member]            
Financing [Line Items]            
Amount borrowed         $ 100.0  
Number of days borrowed         3 days  
Weighted-average interest rate         4.25%  
Revolving Credit Facility [Member] | JPM $1 Billion Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Seventy-One Days [Member]            
Financing [Line Items]            
Amount borrowed   $ 400.0   $ 400.0    
Number of days borrowed   71 days   71 days    
Revolving Credit Facility [Member] | JPM $1 Billion Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Seventy-One Days [Member] | LIBOR [Member]            
Financing [Line Items]            
Weighted-average interest rate   3.48%   3.48%    
Revolving Credit Facility [Member] | JPM $500 Million Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member]            
Financing [Line Items]            
Amounts outstanding   $ 400.0   $ 400.0   0.0
Amount borrowed   $ 400.0 $ 75.0 $ 400.0 $ 400.0  
Number of days borrowed   71 days 19 days 78 days 39 days  
Weighted-average interest rate   3.48% 2.19% 3.57% 2.69%  
Weighted-average amount borrowed   $ 400.0 $ 75.0 $ 374.1 $ 147.2  
Revolving Credit Facility [Member] | JPM $500 Million Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Seven Days [Member]            
Financing [Line Items]            
Amount borrowed         $ 300.0  
Number of days borrowed         7 days  
Revolving Credit Facility [Member] | JPM $500 Million Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Seven Days [Member] | LIBOR [Member]            
Financing [Line Items]            
Weighted-average interest rate         2.13%  
Revolving Credit Facility [Member] | JPM $500 Million Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Nineteen Days [Member]            
Financing [Line Items]            
Amount borrowed     $ 75.0      
Number of days borrowed     19 days      
Revolving Credit Facility [Member] | JPM $500 Million Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Nineteen Days [Member] | LIBOR [Member]            
Financing [Line Items]            
Weighted-average interest rate     2.19%      
Revolving Credit Facility [Member] | JPM $500 Million Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Thirty Days [Member]            
Financing [Line Items]            
Amount borrowed         $ 75.0  
Number of days borrowed         30 days  
Revolving Credit Facility [Member] | JPM $500 Million Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Thirty Days [Member] | LIBOR [Member]            
Financing [Line Items]            
Weighted-average interest rate         2.19%  
Revolving Credit Facility [Member] | JPM $500 Million Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Seventy-One Days [Member]            
Financing [Line Items]            
Amount borrowed   $ 400.0   $ 400.0    
Number of days borrowed   71 days   71 days    
Revolving Credit Facility [Member] | JPM $500 Million Credit Facility [Member] | JP Morgan Chase Bank, N.A. [Member] | Seventy-One Days [Member] | LIBOR [Member]            
Financing [Line Items]            
Weighted-average interest rate   3.48%   3.48%    
Revolving Credit Facility [Member] | PNC $150 Million Credit Facility [Member] | PNC Bank, National Association [Member]            
Financing [Line Items]            
Amounts outstanding   $ 53.6   $ 53.6   0.0
Amount borrowed   $ 58.9 $ 59.9 $ 58.9 $ 59.9  
Number of days borrowed   90 days 90 days 269 days 269 days  
Weighted-average interest rate   2.94% 2.01% 2.72% 1.83%  
Weighted-average amount borrowed   $ 57.7 $ 59.1 $ 57.0 $ 57.6  
Standby Letters of Credit [Member]            
Financing [Line Items]            
Maximum borrowing capacity   72.7   72.7   56.8
Amounts outstanding   $ 0.0 $ 0.0 $ 0.0 $ 0.0 $ 0.0
Minimum [Member] | Standby Letters of Credit [Member]            
Financing [Line Items]            
Expiration date       Apr. 01, 2019    
Maximum [Member] | Standby Letters of Credit [Member]            
Financing [Line Items]            
Expiration date       Nov. 01, 2020