Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		60 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Feb. 28, 2017	Apr. 30, 2012
Common Stock Programs
Shares purchased (in shares)			91,300,000
Total cost of shares purchased	$ 126.0		$ 7,300.0
Treasury stock acquired, additional transaction costs	$ 0.6
Weighted average shares outstanding
Shares for basic earnings per share (in shares)	264,800,000	271,700,000
Dilutive effect of potentially issuable shares (in shares)	2,200,000	2,000,000
Shares for diluted earnings per share (in shares)	267,000,000	273,700,000
Number of shares excluded from the calculation of diluted earnings per share (in shares)	0	500,000
Share Repurchase Program of 2014
Common Stock Programs
Share repurchase authorization limit (up to)				$ 5,000.0
Share repurchase, remaining authorization limit (shares)	$ 7,700.0		$ 7,700.0
2012 - Share Repurchase Program
Common Stock Programs
Share repurchase authorization limit (up to)					$ 5,000.0
Shares purchased (in shares)	1,100,000	7,700,000
Average price per share of stock repurchased (in usd per share)	$ 114.46	$ 97.92
Total cost of shares purchased	$ 125.0	$ 750.0