Consolidated Statement of Comprehensive Income - 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]
Net income	$ 765	$ 685	$ 2,160	$ 1,807
Other comprehensive income (loss), net of related taxes:
Foreign currency translation, net of related taxes	(57)	259	(244)	785
Net unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment and net of related taxes	(218)	47	(475)	519
Net unrealized gains (losses) on available-for-sale securities designated in fair value hedges, net of related taxes	20	4	29	13
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, net of related taxes	2	1	1	3
Net unrealized gains (losses) on cash flow hedges, net of related taxes	30	(27)	(27)	(274)
Net unrealized gains (losses) on retirement plans, net of related taxes	0	2	14	10
Other comprehensive income (loss)	(223)	286	(702)	1,056
Total comprehensive income	$ 542	$ 971	$ 1,458	$ 2,863