Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net Income (Loss) Attributable to Parent									$ 656.0	$ 618.9	$ 554.4
Weighted-average number of common shares outstanding, Basic									386.1	383.3	389.6
Restricted stock, stock options and other equity awards									5.1	5.7	7.7
Weighted-average number of common shares outstanding, Diluted									391.2	389.0	397.3
Basic	$ 0.85	$ 0.43	$ 0.44	$ (0.02)	$ 0.85	$ 0.42	$ 0.38	$ (0.04)	$ 1.70	$ 1.61	$ 1.42
Diluted	$ 0.84	$ 0.42	$ 0.43	$ (0.02)	$ 0.84	$ 0.41	$ 0.37	$ (0.04)	$ 1.68	$ 1.59	$ 1.40