Equity Activity in OCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Equity [Abstract]
Net income	$ 3,196	$ 1,960	$ 7,278	$ 8,488
Other comprehensive (loss) income, net of tax effect:
Changes in net unrealized gains (losses) on AFS securities (net of tax of $18 and $58, respectively, for the three months ended and net of tax of $3 and $89, respectively, for the nine months ended)	33	(107)	(6)	(164)
Reclassification adjustment for OTTI recognized in net income (net of tax of $1 and $2, respectively, for the three months ended and net of tax of $12 and $66, respectively, for the nine months ended)	2	3	22	121
Reclassification adjustment for gains on AFS securities included in net income (net of tax of $129 and $32, respectively, for the three months ended and net of tax of $266 and $265, respectively, for the nine months ended)	(240)	(73)	(494)	(505)
Other	(2)	430	(6)	428
Total other comprehensive income (loss)	(207)	253	(484)	(120)
Total comprehensive income	2,989	2,213	6,794	8,368
Other Comprehensive Income (Loss), Tax, Parenthetical Disclosures [Abstract]
Changes in net unrealized gains (losses) on AFS securities (net of tax of $18 and $58, respectively, for the three months ended and net of tax of $3 and $89, respectively, for the nine months ended)	18	(58)	(3)	(89)
Reclassification adjustment for OTTI recognized in net income (net of tax of $1 and $2, respectively, for the three months ended and net of tax of $12 and $66, respectively, for the nine months ended)	1	2	12	66
Reclassification adjustment for gains on AFS securities included in net income (net of tax of $129 and $32, respectively, for the three months ended and net of tax of $266 and $265, respectively, for the nine months ended)	$ 129	$ 32	$ 266	$ 265