Income Taxes (Details 3) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance, January 1	$ 1,044,000,000us-gaap_UnrecognizedTaxBenefits	$ 1,230,000,000us-gaap_UnrecognizedTaxBenefits	$ 1,223,000,000us-gaap_UnrecognizedTaxBenefits
Increases:
Current year tax positions	4,000,000	124,000,000	51,000,000
Tax positions related to prior years	111,000,000	176,000,000	64,000,000
Decreases:
Tax positions related to prior years	(181,000,000)	(371,000,000)	(44,000,000)
Settlements with tax authorities	(67,000,000)	(94,000,000)	(25,000,000)
Lapse of statute of limitations	(1,000,000)	(21,000,000)	(37,000,000)
Effects of foreign currency translations	(1,000,000)	0	(2,000,000)
Balance, December 31	$ 909,000,000us-gaap_UnrecognizedTaxBenefits	$ 1,044,000,000us-gaap_UnrecognizedTaxBenefits	$ 1,230,000,000us-gaap_UnrecognizedTaxBenefits

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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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