Variable Interest Entities - Summary of Assets and Liabilities Related to Consolidated Variable Interest Entities (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013		Jun. 30, 2013
Variable Interest Entity [Line Items]
Interest bearing deposits with banks	$ 23,946		$ 19,614
Securities held-to-maturity	1,205		1,358
Other assets	8,321		8,140
Total assets	182,218	[1]	185,487	[1]	189,524
Other	3,388		3,558
Long-term debt	24,604		22,847
Total liabilities	165,234	[1]	169,023	[1]
Variable interest entities [Member]
Variable Interest Entity [Line Items]
Interest bearing deposits with banks	3		5
Securities held-to-maturity	157		200
Other assets	458		502
Total assets	618		707
Other	71		93
Long-term debt	92		92
Total liabilities	163		185
Asset-backed commercial paper conduits [Member]
Variable Interest Entity [Line Items]
Interest bearing deposits with banks	3		5
Securities held-to-maturity	157		200
Other assets	40		45
Total assets	200		250
Other	0		3
Total liabilities	0		3
Low Income Housing Limited Liability Partnership [Member]
Variable Interest Entity [Line Items]
Other assets	418		457
Total assets	418		457
Other	71		90
Long-term debt	92		92
Total liabilities	$ 163		$ 182

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") as of June 30, 2014 and December 31, 2013 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 16, "Variable Interest Entities," for additional information. Assets: Interest bearing deposits with banks, $3 million and $5 million, Securities held-to-maturity, $157 million and $200 million Other assets $458 million and $502 million. Total assets $618 million and $707 million respectively. Liabilities: Long-term debt $92 million and $92 million, Interest, taxes and other liabilities $71 million and $93 million. Total liabilities $163 million and $185 million, respectively.