Fair Value (Schedule of Availability of Significant Unobservable Inputs by Balance Sheet Classification) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
Assets:
Investment securities available for sale	$ 99,162,000,000		$ 99,174,000,000
Asset-backed securities, student loans
Assets:
Investment securities available for sale	14,280,000,000	[1]	14,542,000,000	[1]
Asset-backed securities, credit cards
Assets:
Investment securities available for sale	7,237,000,000		8,210,000,000
Asset-backed securities, other
Assets:
Investment securities available for sale	4,880,000,000		5,064,000,000
Non-U.S. debt securities, mortgage-backed securities
Assets:
Investment securities available for sale	11,196,000,000		11,029,000,000
Non-U.S. debt securities, asset-backed securities
Assets:
Investment securities available for sale	4,994,000,000		5,390,000,000
Non-U.S. debt securities, other
Assets:
Investment securities available for sale	4,984,000,000		4,727,000,000
State and political subdivisions
Assets:
Investment securities available for sale	10,444,000,000		10,263,000,000
Collateralized mortgage obligations
Assets:
Investment securities available for sale	5,262,000,000		5,269,000,000
Other U.S.debt securities
Assets:
Investment securities available for sale	4,946,000,000		4,980,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3)
Assets:
Assets, fair value disclosure	6,069,000,000		7,564,000,000
Liabilities:
Liabilities, fair value disclosure	17,000,000		26,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Derivative instruments, liabilities
Liabilities:
Derivative instruments, foreign exchange contracts, liabilities	8,000,000		17,000,000
Derivative instruments, other, liabilities	9,000,000		9,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Derivative instruments, assets
Assets:
Derivative instruments, foreign exchange contracts, assets	6,000,000		19,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | U.S. Treasury and federal agencies, mortgage-backed securities
Assets:
Investment securities available for sale	100,000,000		716,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, student loans
Assets:
Investment securities available for sale	333,000,000		423,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, credit cards
Assets:
Investment securities available for sale			24,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, other
Assets:
Investment securities available for sale	4,304,000,000		4,532,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, mortgage-backed securities
Assets:
Investment securities available for sale			375,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, asset-backed securities
Assets:
Investment securities available for sale	612,000,000		798,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, other
Assets:
Investment securities available for sale	462,000,000		464,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | State and political subdivisions
Assets:
Investment securities available for sale	42,000,000		43,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Collateralized mortgage obligations
Assets:
Investment securities available for sale	202,000,000		162,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Other U.S.debt securities
Assets:
Investment securities available for sale	8,000,000		8,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member]
Assets:
Assets, fair value disclosure	149,000,000	[2]	191,000,000	[2]
Liabilities:
Liabilities, fair value disclosure	17,000,000	[2]	26,000,000	[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	8,000,000	[2]	17,000,000	[2]
Derivative instruments, other, liabilities	9,000,000	[2]	9,000,000	[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	6,000,000	[2]	19,000,000	[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	14,000,000	[2]	13,000,000	[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]	24,000,000	[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	87,000,000	[2]	92,000,000	[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	42,000,000	[2]	43,000,000	[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	5,920,000,000	[3]	7,373,000,000	[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	100,000,000	[3]	716,000,000	[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	319,000,000	[3]	410,000,000	[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	4,217,000,000	[3]	4,440,000,000	[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			375,000,000	[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	612,000,000	[3]	798,000,000	[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	462,000,000	[3]	464,000,000	[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	202,000,000	[3]	162,000,000	[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	$ 8,000,000	[3]	$ 8,000,000	[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.