Stock Repurchases, Dividends and Earnings per Share - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions |
1 Months Ended | 3 Months Ended | ||||
---|---|---|---|---|---|---|
Feb. 28, 2018 |
Oct. 31, 2017 |
Mar. 31, 2018 |
Mar. 31, 2017 |
Dec. 31, 2017 |
Sep. 30, 2017 |
|
Equity [Abstract] | ||||||
Stock repurchased and pending settlement (in shares) | 0.2 | 0.2 | ||||
Stock repurchased and pending settlement, liability | $ 14.9 | $ 10.9 | ||||
Additional shares authorized for repurchase, value | $ 2,000.0 | |||||
Remaining authorized repurchase amount | $ 1,600.0 | $ 98.4 | ||||
Quarterly dividend declared (in dollars per share) | $ 0.345 | $ 0.345 | $ 0.32 | |||
Cash dividends declared | $ 113.3 | |||||
Quarterly dividend payable | $ 113.3 | $ 114.4 |