Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 661	$ 502
Other comprehensive income (loss), net of related taxes:
Foreign currency translation, net of related taxes of $21, ($11) and ($101), respectively	151	91
Net unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment and net of related taxes of $272, ($119), and ($195), respectively	(135)	201
Net unrealized gains (losses) on available-for-sale securities designated in fair value hedges, net of related taxes of $16, $16 and $5, respectively	4	6
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, net of related taxes of $3, $5 and $8, respectively	0	1
Net unrealized gains (losses) on cash flow hedges, net of related taxes of ($181), ($42) and $24, respectively	(97)	(70)
Net unrealized gains (losses) on retirement plans, net of related taxes of $8, $1 and $51, respectively	12	6
Other comprehensive income (loss)	(65)	235
Total comprehensive income	$ 596	$ 737