Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Foreign currency translation, Taxes	$ (114)	$ (110)	$ (62)	$ 13
Change in net unrealized losses on available-for-sale securities, Taxes	(20)	177	(136)	308
Change in net unrealized losses on available-for-sale securities designated in fair value hedges, Taxes	1	0	22	5
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, Taxes	1	0	3	1
Change in net unrealized losses on cash flow hedges, Taxes	9	(113)	(10)	(164)
Change in unrealized losses on retirement plans, Taxes	$ 0	$ (1)	$ 3	$ 2