Consolidated Statement of Comprehensive Income - 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]
Net income	$ 734	$ 620	$ 1,395	$ 1,122
Other comprehensive income (loss), net of related taxes:
Foreign currency translation, net of related taxes of ($62) and $13, respectively	(338)	435	(187)	526
Net unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment and net of related taxes of ($136) and $308, respectively	(122)	271	(257)	472
Net unrealized gains (losses) on available-for-sale securities designated in fair value hedges, net of related taxes of $22 and $5, respectively	5	3	9	9
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, net of related taxes of $3 and $1, respectively	(1)	1	(1)	2
Net unrealized gains (losses) on cash flow hedges, net of related taxes of ($10) and ($164), respectively	40	(177)	(57)	(247)
Net unrealized gains (losses) on retirement plans, net of related taxes of $3 and $2, respectively	2	2	14	8
Other comprehensive income (loss)	(414)	535	(479)	770
Total comprehensive income	$ 320	$ 1,155	$ 916	$ 1,892