Fair Value (Fair Value Inputs, Assets and Liabilities, Quantitative Information) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	$ 99,174		$ 109,682
Asset-backed securities, student loans
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	14,542	[1]	16,421	[1]
Asset-backed securities, credit cards
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	8,210		9,986
Asset-backed securities, other
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	5,064		4,677
State and political subdivisions
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	10,263		7,551
Pricing Methods with Significant Unobservable Market Inputs (Level 3)
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value disclosure	7,564		6,980
Liabilities, fair value disclosure	26		115
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Derivative instruments, liabilities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative instruments, foreign exchange contracts, liabilities	17		106
Derivative instruments, other, liabilities	9		9
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Derivative instruments, assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative instruments, foreign exchange contracts, assets	19		113
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, student loans
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	423		588
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, credit cards
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	24		67
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, other
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	4,532		3,994
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | State and political subdivisions
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	43		48
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Discounted cash flows | Derivative instruments, liabilities | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Participant redemptions	7.50%	[2]	6.70%	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Discounted cash flows | Asset-backed securities, student loans | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Credit spread	3.50%		6.70%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Discounted cash flows | Asset-backed securities, credit cards | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Credit spread	2.00%		7.10%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Discounted cash flows | Asset-backed securities, other | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Credit spread	1.50%		1.50%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Discounted cash flows | State and political subdivisions | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Credit spread	1.70%		1.90%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Option model | Derivative instruments, liabilities | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Volatility	11.20%		9.80%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Option model | Derivative instruments, assets | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Volatility	11.40%		9.80%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value disclosure	191	[3]	343	[3]
Liabilities, fair value disclosure	26	[3]	115	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Derivative instruments, liabilities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative instruments, foreign exchange contracts, liabilities	17	[3]	106	[3]
Derivative instruments, other, liabilities	9	[3]	9	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Derivative instruments, assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative instruments, foreign exchange contracts, assets	19	[3]	113	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, student loans
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	13	[3]	12	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, credit cards
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	24	[3]	67	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, other
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	92	[3]	103	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | State and political subdivisions
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	43	[3]	48	[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Discounted cash flows | Derivative instruments, liabilities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative instruments, other, liabilities	9	[2]	9	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Discounted cash flows | Asset-backed securities, student loans
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	13		12
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Discounted cash flows | Asset-backed securities, credit cards
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	24		67
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Discounted cash flows | Asset-backed securities, other
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	92		103
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Discounted cash flows | State and political subdivisions
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available for sale	43		48
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Option model | Derivative instruments, liabilities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative instruments, foreign exchange contracts, liabilities	17		106
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Option model | Derivative instruments, assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative instruments, foreign exchange contracts, assets	$ 19		$ 113

[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] Relates to stable value wrap contracts; refer to the sensitivity discussion following the tables presented below, and to note 11.

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