Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Foreign currency translation, Taxes	$ 3	$ (7)	$ (59)	$ 6
Change in net unrealized losses on available-for-sale securities, Taxes	(66)	28	(202)	336
Change in net unrealized losses on available-for-sale securities designated in fair value hedges, Taxes	(12)	4	10	9
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, Taxes	1	1	4	2
Change in net unrealized losses on cash flow hedges, Taxes	(5)	(15)	(15)	(179)
Change in unrealized losses on retirement plans, Taxes	$ 2	$ 0	$ 5	$ 2