Shareholders' Equity - Ordinary Shares (Details) - USD ($) $ / shares in Units, shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 31, 2015	Nov. 30, 2014	Apr. 30, 2012
Common Stock Programs
Cost of shares repurchased	$ 1,257,000,000	$ 1,550,000,000	$ 2,250,000,000
Treasury Stock, Acquired, Additional Transaction Costs	$ 6,000,000
Share Repurchase Program
Common Stock Programs
Number of shares repurchased (in shares)	12.2	16.0
Average price per share of shares purchased under share repurchase program (in dollars per share)	$ 102.66	$ 97.04
Cost of shares repurchased	$ 1,300,000,000	$ 1,600,000,000
Share Repurchase Programs of 2012 and 2014
Common Stock Programs
Share repurchase, remaining authorization limit	$ 2,800,000,000
Share Repurchase Program of 2012
Common Stock Programs
Share repurchase authorization limit						$ 5,000,000,000.0
Number of shares repurchased (in shares)	90.2
Cost of shares repurchased	$ 7,200,000,000
Share Repurchase Program of 2014
Common Stock Programs
Share repurchase authorization limit				$ 5,000,000,000	$ 5,000,000,000.0