Shareholders' Equity (Details) - USD ($)	3 Months Ended		9 Months Ended		78 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Feb. 28, 2017	Nov. 30, 2014	Apr. 30, 2012
Common Stock Programs
Shares purchased (in shares)					117,000,000
Total cost of shares purchased			$ 1,256,000,000	$ 1,913,000,000	$ 10,800,000,000
Weighted average shares outstanding
Basic weighted average ordinary shares outstanding (in shares)	244,000,000	255,600,000	246,200,000	260,900,000
Dilutive effect of potentially issuable shares (in shares)	1,600,000	1,700,000	1,500,000	2,000,000
Diluted weighted average ordinary shares outstanding (in shares)	245,600,000	257,300,000	247,700,000	262,900,000
Number of shares excluded from the calculation of diluted earnings per share (in shares)	0	0	0	0
2012 - Share Repurchase Program
Common Stock Programs
Share repurchase authorization limit (up to)								$ 5,000,000,000.0
Shares purchased (in shares)	2,100,000	5,400,000	8,800,000	14,500,000
Total cost of shares purchased	$ 300,000,000	$ 749,000,000	$ 1,250,000,000	$ 1,903,000,000
Share Repurchase Program of 2014
Common Stock Programs
Share repurchase authorization limit (up to)	15,000,000,000.0		15,000,000,000.0		15,000,000,000.0	$ 5,000,000,000.0
Share repurchase, remaining authorization limit (in shares)	$ 4,200,000,000		$ 4,200,000,000		$ 4,200,000,000
Share Repurchase Program Of 2017
Common Stock Programs
Share repurchase authorization limit (up to)							$ 5,000,000,000.0