Derivative Financial Instruments - Schedule of Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Derivative Asset [Abstract]
Derivatives accounted for as fair value hedges	$ 0		$ 7
Derivatives accounted for as cash flow hedges	271	[1]	506	[1]
Non-qualifying hedge activities	24	[1]	23	[1]
Total Derivative Financial Assets	1,107	[2]	1,683	[2]
Less: Gross amounts offset in the balance sheet	1,107	[3]	1,683	[3]
Net amounts of derivative financial assets and liabilities presented in the balance sheet	0	[4]	0	[4]
Derivative Liability [Abstract]
Derivatives accounted for as fair value hedges	0		0
Derivatives accounted for as cash flow hedges	(166)		(512)
Derivatives not designated as hedging instruments	(171)		(1,118)
Total Derivative Financial Liabilities	(337)	[2]	(1,630)	[2]
Less: Gross amounts offset in the balance sheet	(337)	[3]	(1,608)	[3]
Net amounts of derivative financial assets and liabilities presented in the balance sheet	0	[4]	(22)	[4]
Debt [Member]
Derivative Asset [Abstract]
Non-qualifying hedge activities	812	[1]	1,147	[1]
Derivative Liability [Abstract]
Derivatives not designated as hedging instruments	0		0
Interest rate swaps [Member]
Derivative Asset [Abstract]
Derivatives accounted for as fair value hedges	0		7
Derivatives accounted for as cash flow hedges	16	[1]	24	[1]
Non-qualifying hedge activities	24	[1]	23	[1]
Derivative Liability [Abstract]
Derivatives accounted for as fair value hedges	0		0
Derivatives accounted for as cash flow hedges	(138)		(474)
Derivatives not designated as hedging instruments	(171)		(1,111)
Interest rate swaps [Member] | Debt [Member]
Derivative Asset [Abstract]
Non-qualifying hedge activities	270	[1]	469	[1]
Derivative Liability [Abstract]
Derivatives not designated as hedging instruments	0		0
Currency swaps [Member]
Derivative Asset [Abstract]
Derivatives accounted for as fair value hedges	0		0
Derivatives accounted for as cash flow hedges	255	[1]	482	[1]
Non-qualifying hedge activities	0	[1]	0	[1]
Derivative Liability [Abstract]
Derivatives accounted for as fair value hedges	0		0
Derivatives accounted for as cash flow hedges	(28)		(38)
Derivatives not designated as hedging instruments	0		(7)
Currency swaps [Member] | Debt [Member]
Derivative Asset [Abstract]
Non-qualifying hedge activities	542	[1]	678	[1]
Derivative Liability [Abstract]
Derivatives not designated as hedging instruments	$ 0		$ 0

[1] Derivative assets related to cash flow hedges and non-qualifying hedge activities are recorded within other assets in our consolidated balance sheet.

[2] All of our derivatives are bilateral over-the-counter ("OTC") derivatives.

[3] Represents the netting of derivative receivable and payable balances for the same counterparty under an enforceable netting agreement. Gross amounts offset in the balance sheet includes collateral received as of December 31, 2013 and December 31, 2012 of $811 million and $75 million, respectively. At December 31, 2013 and December 31, 2012, we did not have any financial instrument collateral received/posted.

[4] At December 31, 2013 and December 31, 2012, we had not received any cash or financial instruments not subject to an enforceable master netting agreement.