Fair Value (Schedule of Availability of Significant Unobservable Inputs by Balance Sheet Classification) (Details) (Pricing Methods with Significant Unobservable Market Inputs (Level 3), USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Assets:
Assets, fair value disclosure	$ 7,380		$ 6,980
Liabilities:
Liabilities, fair value disclosure	64		115
Derivative instruments, liabilities
Liabilities:
Derivative instruments, foreign exchange contracts, liabilities	55		106
Derivative instruments, other, liabilities	9		9
Derivative instruments, assets
Assets:
Derivative instruments, foreign exchange contracts, assets	77		113
U.S. Treasury and federal agencies, mortgage-backed securities
Assets:
Available-for-sale securities	741		825
Asset-backed securities, student loans
Assets:
Available-for-sale securities	368		588
Asset-backed securities, credit cards
Assets:
Available-for-sale securities	24		67
Asset-backed securities, other
Assets:
Available-for-sale securities	4,350		3,994
Non-U.S. debt securities, mortgage-backed securities
Assets:
Available-for-sale securities	340		555
Non-U.S. debt securities, asset-backed securities
Assets:
Available-for-sale securities	799		524
Non-U.S. debt securities, other
Assets:
Available-for-sale securities	441		140
State and political subdivisions
Assets:
Available-for-sale securities	44		48
Collateralized mortgage obligations
Assets:
Available-for-sale securities	187		117
Other U.S.debt securities
Assets:
Available-for-sale securities	9		9
Significant Unobservable Inputs Readily Available [Member]
Assets:
Assets, fair value disclosure	259	[1]	343	[1]
Liabilities:
Liabilities, fair value disclosure	64	[1]	115	[1]
Significant Unobservable Inputs Readily Available [Member] | Derivative instruments, liabilities
Liabilities:
Derivative instruments, foreign exchange contracts, liabilities	55	[1]	106	[1]
Derivative instruments, other, liabilities	9	[1]	9	[1]
Significant Unobservable Inputs Readily Available [Member] | Derivative instruments, assets
Assets:
Derivative instruments, foreign exchange contracts, assets	77	[1]	113	[1]
Significant Unobservable Inputs Readily Available [Member] | U.S. Treasury and federal agencies, mortgage-backed securities
Assets:
Available-for-sale securities	0	[1]	0	[1]
Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, student loans
Assets:
Available-for-sale securities	13	[1]	12	[1]
Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, credit cards
Assets:
Available-for-sale securities	24	[1]	67	[1]
Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, other
Assets:
Available-for-sale securities	101	[1]	103	[1]
Significant Unobservable Inputs Readily Available [Member] | Non-U.S. debt securities, mortgage-backed securities
Assets:
Available-for-sale securities	0	[1]	0	[1]
Significant Unobservable Inputs Readily Available [Member] | Non-U.S. debt securities, asset-backed securities
Assets:
Available-for-sale securities	0	[1]	0	[1]
Significant Unobservable Inputs Readily Available [Member] | Non-U.S. debt securities, other
Assets:
Available-for-sale securities	0	[1]	0	[1]
Significant Unobservable Inputs Readily Available [Member] | State and political subdivisions
Assets:
Available-for-sale securities	44	[1]	48	[1]
Significant Unobservable Inputs Readily Available [Member] | Collateralized mortgage obligations
Assets:
Available-for-sale securities	0	[1]	0	[1]
Significant Unobservable Inputs Readily Available [Member] | Other U.S.debt securities
Assets:
Available-for-sale securities	0	[1]	0	[1]
Significant Unobservable Inputs Not Readily Available [Member]
Assets:
Assets, fair value disclosure	7,121	[2]	6,637	[2]
Liabilities:
Liabilities, fair value disclosure	0	[2]	0	[2]
Significant Unobservable Inputs Not Readily Available [Member] | Derivative instruments, liabilities
Liabilities:
Derivative instruments, foreign exchange contracts, liabilities	0	[2]	0	[2]
Derivative instruments, other, liabilities	0	[2]	0	[2]
Significant Unobservable Inputs Not Readily Available [Member] | Derivative instruments, assets
Assets:
Derivative instruments, foreign exchange contracts, assets	0	[2]	0	[2]
Significant Unobservable Inputs Not Readily Available [Member] | U.S. Treasury and federal agencies, mortgage-backed securities
Assets:
Available-for-sale securities	741	[2]	825	[2]
Significant Unobservable Inputs Not Readily Available [Member] | Asset-backed securities, student loans
Assets:
Available-for-sale securities	355	[2]	576	[2]
Significant Unobservable Inputs Not Readily Available [Member] | Asset-backed securities, credit cards
Assets:
Available-for-sale securities	0	[2]	0	[2]
Significant Unobservable Inputs Not Readily Available [Member] | Asset-backed securities, other
Assets:
Available-for-sale securities	4,249	[2]	3,891	[2]
Significant Unobservable Inputs Not Readily Available [Member] | Non-U.S. debt securities, mortgage-backed securities
Assets:
Available-for-sale securities	340	[2]	555	[2]
Significant Unobservable Inputs Not Readily Available [Member] | Non-U.S. debt securities, asset-backed securities
Assets:
Available-for-sale securities	799	[2]	524	[2]
Significant Unobservable Inputs Not Readily Available [Member] | Non-U.S. debt securities, other
Assets:
Available-for-sale securities	441	[2]	140	[2]
Significant Unobservable Inputs Not Readily Available [Member] | State and political subdivisions
Assets:
Available-for-sale securities	0	[2]	0	[2]
Significant Unobservable Inputs Not Readily Available [Member] | Collateralized mortgage obligations
Assets:
Available-for-sale securities	187	[2]	117	[2]
Significant Unobservable Inputs Not Readily Available [Member] | Other U.S.debt securities
Assets:
Available-for-sale securities	$ 9	[2]	$ 9	[2]

[1] Information with respect to these model-priced financial assets and liabilities is provided in the preceding table.

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