Share Repurchases and Dividends (Details) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 31, 2017
Stockholders' Equity Note [Abstract]
Number of shares repurchased (in shares)		4,900,000	10,700,000
Amount paid		$ 399,400,000	$ 736,900,000
Weighted average cost per share (in dollars per share)		$ 82.13	$ 69.06
Shares pending settlement (in shares)		0
Shares adding to existing share repurchase program					$ 2,000,000,000.0
Remaining authorized purchase capacity		$ 704,600,000
Quarterly dividend per share (in dollars per share)	$ 0.405	$ 1.56	$ 1.44	$ 1.33
Cash dividends declared		$ 499,400,000	$ 468,400,000	$ 446,300,000
Quarterly dividend payable		$ 129,200,000	$ 121,000,000.0