The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Goodwill, Intangible Assets and Impairment - Additional Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended			0 Months Ended
	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Apr. 30, 2013	Mar. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 315us-gaap_Goodwill	$ 315us-gaap_Goodwill	$ 315us-gaap_Goodwill	$ 0us-gaap_Goodwill
WACC utilized in the company's analysis using the income approach (as a percentage)		17.50%us-gaap_FairValueInputsDiscountRate
Goodwill impairment	74us-gaap_GoodwillImpairmentLoss	0us-gaap_GoodwillImpairmentLoss	74us-gaap_GoodwillImpairmentLoss
Goodwill additions		0us-gaap_GoodwillAcquiredDuringPeriod	389us-gaap_GoodwillAcquiredDuringPeriod
Definite-lived intangible assets	1,381us-gaap_FiniteLivedIntangibleAssetsNet	794us-gaap_FiniteLivedIntangibleAssetsNet	1,381us-gaap_FiniteLivedIntangibleAssetsNet
Impairment of definite-lived intangible assets	384	384	384
Amortization of intangible assets		587us-gaap_AmortizationOfIntangibleAssets	703us-gaap_AmortizationOfIntangibleAssets	350us-gaap_AmortizationOfIntangibleAssets
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2015		373
2016		237
2017		103
2018		81
Super Media, Inc.
Finite-Lived Intangible Assets [Line Items]
Goodwill					389	389
Goodwill additions					$ 389