Accounting Policies (Details) (USD $) In Millions, unless otherwise specified							3 Months Ended	6 Months Ended
	Jun. 30, 2014		Dec. 31, 2013		Jun. 30, 2014 Cumulative effect of adopting ASU 2014-01 [Member]	Jun. 30, 2013 Cumulative effect of adopting ASU 2014-01 [Member]	Jun. 30, 2014 Cumulative effect of adopting ASU 2014-01 [Member] Low Income Housing Tax Credit Investments [Member]	Jun. 30, 2014 Cumulative effect of adopting ASU 2014-01 [Member] Low Income Housing Tax Credit Investments [Member]	Jun. 30, 2014 Retained Earnings [Member] Cumulative effect of adopting ASU 2014-01 [Member]	Jun. 30, 2013 Retained Earnings [Member] Cumulative effect of adopting ASU 2014-01 [Member]
Charge off threshold - small business commercial loans	$ 1
Amortization recognized for low income housing tax credits associated with adoption of ASU 2014-01							46	90
Tax credits recognized for low income housing tax credits associated with adoption of ASU 2014-01							50	100
Other tax benefits recognized for low income housing tax credits associated with adoption of ASU 2014-01							17	33
Equity investments	10,583	[1],[2]	10,560	[1],[2]			1,900	1,900
Cumulative effect adjustment					$ (60)	$ (45)			$ (74)	$ (55)

[1] Amounts for 2013 periods have been updated to reflect the first quarter 2014 adoption of Accounting Standards Update (ASU) 2014-01 related to investments in low income housing tax credits.

[2] Amounts represent the assets or liabilities of consolidated variable interest entities (VIEs).