Fair Value (Schedule of Availability of Significant Unobservable Inputs by Balance Sheet Classification) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Assets:
Investment securities available for sale	$ 98,546		$ 99,174
Asset-backed securities, student loans
Assets:
Investment securities available for sale	13,962	[1]	14,542	[1]
Asset-backed securities, credit cards
Assets:
Investment securities available for sale	6,566		8,210
Asset-backed securities, other
Assets:
Investment securities available for sale	4,635		5,064
Non-U.S. debt securities, mortgage-backed securities
Assets:
Investment securities available for sale	11,435		11,029
Non-U.S. debt securities, asset-backed securities
Assets:
Investment securities available for sale	4,200		5,390
Non-U.S. debt securities, other
Assets:
Investment securities available for sale	5,757		4,727
State and political subdivisions
Assets:
Investment securities available for sale	10,617		10,263
Collateralized mortgage obligations
Assets:
Investment securities available for sale	5,374		5,269
Other U.S. debt securities
Assets:
Investment securities available for sale	4,842		4,980
Pricing Methods with Significant Unobservable Market Inputs (Level 3)
Assets:
Assets, fair value disclosure	5,756		7,564
Liabilities:
Liabilities, fair value disclosure	19		26
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Derivative instruments, liabilities
Liabilities:
Derivative instruments, foreign exchange contracts, liabilities	10		17
Derivative instruments, other, liabilities	9		9
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Derivative instruments, assets
Assets:
Derivative instruments, foreign exchange contracts, assets	10		19
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | U.S. Treasury and federal agencies, mortgage-backed securities
Assets:
Investment securities available for sale	96		716
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, student loans
Assets:
Investment securities available for sale	322		423
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, credit cards
Assets:
Investment securities available for sale			24
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, other
Assets:
Investment securities available for sale	4,061		4,532
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, mortgage-backed securities
Assets:
Investment securities available for sale			375
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, asset-backed securities
Assets:
Investment securities available for sale	506		798
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, other
Assets:
Investment securities available for sale	515		464
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | State and political subdivisions
Assets:
Investment securities available for sale	41		43
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Collateralized mortgage obligations
Assets:
Investment securities available for sale	196		162
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Other U.S. debt securities
Assets:
Investment securities available for sale	9		8
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member]
Assets:
Assets, fair value disclosure	141	[2]	191	[2]
Liabilities:
Liabilities, fair value disclosure	19	[2]	26	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Derivative instruments, liabilities
Liabilities:
Derivative instruments, foreign exchange contracts, liabilities	10	[2]	17	[2]
Derivative instruments, other, liabilities	9	[2]	9	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Derivative instruments, assets
Assets:
Derivative instruments, foreign exchange contracts, assets	10	[2]	19	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | U.S. Treasury and federal agencies, mortgage-backed securities
Assets:
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, student loans
Assets:
Investment securities available for sale	14	[2]	13	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, credit cards
Assets:
Investment securities available for sale	0	[2]	24	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, other
Assets:
Investment securities available for sale	76	[2]	92	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Non-U.S. debt securities, mortgage-backed securities
Assets:
Investment securities available for sale			0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Non-U.S. debt securities, asset-backed securities
Assets:
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Non-U.S. debt securities, other
Assets:
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | State and political subdivisions
Assets:
Investment securities available for sale	41	[2]	43	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Collateralized mortgage obligations
Assets:
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Other U.S. debt securities
Assets:
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member]
Assets:
Assets, fair value disclosure	5,615	[3]	7,373	[3]
Liabilities:
Liabilities, fair value disclosure	0	[3]	0	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Derivative instruments, liabilities
Liabilities:
Derivative instruments, foreign exchange contracts, liabilities	0	[3]	0	[3]
Derivative instruments, other, liabilities	0	[3]	0	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Derivative instruments, assets
Assets:
Derivative instruments, foreign exchange contracts, assets	0	[3]	0	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | U.S. Treasury and federal agencies, mortgage-backed securities
Assets:
Investment securities available for sale	96	[3]	716	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Asset-backed securities, student loans
Assets:
Investment securities available for sale	308	[3]	410	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Asset-backed securities, credit cards
Assets:
Investment securities available for sale			0	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Asset-backed securities, other
Assets:
Investment securities available for sale	3,985	[3]	4,440	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Non-U.S. debt securities, mortgage-backed securities
Assets:
Investment securities available for sale			375	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Non-U.S. debt securities, asset-backed securities
Assets:
Investment securities available for sale	506	[3]	798	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Non-U.S. debt securities, other
Assets:
Investment securities available for sale	515	[3]	464	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | State and political subdivisions
Assets:
Investment securities available for sale	0	[3]	0	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Collateralized mortgage obligations
Assets:
Investment securities available for sale	196	[3]	162	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Other U.S. debt securities
Assets:
Investment securities available for sale	$ 9	[3]	$ 8	[3]

[1] Substantially composed of securities guaranteed by the federal government with respect to at least 97% of defaulted principal and accrued interest on the underlying loans.

[2] Information with respect to these model-priced financial assets and liabilities is provided above in a separate table.

[3] Fair value for these financial assets is measured using non-binding broker or dealer quotes.