Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Foreign currency translation, Taxes	$ 52	$ 123
Change in net unrealized losses on available-for-sale securities, Taxes	(116)	131
Change in net unrealized losses on available-for-sale securities designated in fair value hedges, Taxes	21	5
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, Taxes	2	1
Change in net unrealized losses on cash flow hedges, Taxes	(19)	(51)
Change in unrealized losses on retirement plans, Taxes	$ 3	$ 3