Income Taxes (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current Unrecognized Tax Benefits [Abstract]
Current liability for unrecognized tax benefits	$ 6
Reconciliation Of Changes In Unrecognized Tax Benefits Liabilities/(Assets) [Abstract]
Unrecognized tax benefits at January 1	59us-gaap_UnrecognizedTaxBenefits	115us-gaap_UnrecognizedTaxBenefits	107us-gaap_UnrecognizedTaxBenefits
Increases for positions taken in current year	92	24	29
Increases for positions taken in prior years	21	15	4
Decreases for positions taken in prior years	(14)	(30)	(19)
Payments to and settlements with taxing authorities	(7)	(63)	0
Increases/(decreases) for interest and penalties	1	0	(4)
Lapse of statutes of limitations	(1)	(2)	(2)
Unrecognized tax benefits at December 31	$ 151us-gaap_UnrecognizedTaxBenefits	$ 59us-gaap_UnrecognizedTaxBenefits	$ 115us-gaap_UnrecognizedTaxBenefits

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The net amount of increases and decreases in unrecognized tax benefits for interest and penalties.

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The current portion of the amount recognized for uncertain tax positions as of the balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

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Amount of decrease 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 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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