Annual report pursuant to Section 13 and 15(d)

Quarterly Financial Data (Quarterly Financial Data) (Details)

v3.7.0.1
Quarterly Financial Data (Quarterly Financial Data) (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended 12 Months Ended
May 31, 2017
Feb. 28, 2017
Nov. 30, 2016
Aug. 31, 2016
May 31, 2016
Feb. 29, 2016
Nov. 30, 2015
Aug. 31, 2015
May 31, 2017
May 31, 2016
May 31, 2015
Quarterly Financial Data [Abstract]                      
Service revenue $ 784.6 $ 782.6 $ 760.0 $ 773.5 $ 741.6 $ 740.7 $ 711.3 $ 712.2 $ 3,100.7 $ 2,905.8 $ 2,697.5
Interest on funds held for clients 14.0 13.2 11.4 12.0 12.3 11.9 11.1 10.8 50.6 46.1 42.1
Total revenue 798.6 795.8 771.4 785.5 753.9 752.6 722.4 723.0 3,151.3 2,951.9 2,739.6
Operating income 298.9 306.6 311.1 323.0 276.3 280.0 294.2 296.1 1,239.6 1,146.6 1,053.6
Investment income/(loss), net 1.6 1.2 0.9 1.5 (0.2) 1.7 1.6 1.4 5.2 4.5 6.4
Income before income taxes 300.5 307.8 312.0 324.5 276.1 281.7 295.8 297.5 1,244.8 1,151.1 1,060.0
Income taxes 105.2 105.3 109.9 107.1 98.0 101.3 106.6 88.4 427.5 394.3 385.1
Net income $ 195.3 $ 202.5 $ 202.1 $ 217.4 $ 178.1 $ 180.4 $ 189.2 $ 209.1 $ 817.3 $ 756.8 $ 674.9
Basic earnings per share $ 0.54 [1] $ 0.56 [1] $ 0.56 [1] $ 0.60 [1] $ 0.49 [1] $ 0.50 [1] $ 0.52 [1] $ 0.58 [1] $ 2.27 [1] $ 2.10 [1] $ 1.86
Diluted earnings per share $ 0.54 [1] $ 0.56 [1] $ 0.56 [1] $ 0.60 [1] $ 0.49 [1] $ 0.50 [1] $ 0.52 [1] $ 0.58 [1] $ 2.25 [1] $ 2.09 [1] $ 1.85
Weighted-average common shares outstanding 359.3 359.0 360.2 361.0 360.3 360.5 360.7 361.1 359.8 360.7 362.9
Weighted-average common shares outstanding, assuming dilution 362.1 361.8 362.6 364.1 362.6 362.2 362.3 362.8 362.6 362.5 364.6
Cash dividends per common share $ 0.46 $ 0.46 $ 0.46 $ 0.46 $ 0.42 $ 0.42 $ 0.42 $ 0.42 $ 1.84 $ 1.68 $ 1.52
Total net realized gains       $ 0.1 [2]   $ 0.1 [2]     $ 0.1 [2] $ 0.1 [2] $ 0.3
[1] Each quarter is a discrete period and the sum of the four quarters' basic and diluted earnings per share amounts may not equal the full year amount.
[2] Total net realized gains on the combined funds held for clients and corporate investment portfolios.