Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

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Amount of increase (decrease) of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair Value Disclosure Rollforward (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Nonrecurring fair value adjustments	$ 26us-gaap_AssetImpairmentCharges	$ 167us-gaap_AssetImpairmentCharges	$ 161us-gaap_AssetImpairmentCharges
NBCUniversal Media, LLC [Member]
Nonrecurring fair value adjustments	26	167	161
Contractual Obligation [Member]
Beginning balance	747
Fair value adjustments	208
Payments	(72)
Ending balance	883
Contractual Obligation [Member] \| NBCUniversal Media, LLC [Member]
Beginning balance	747
Fair value adjustments	208
Payments	(72)
Ending balance	883
Contingent Consideration [Member]
Beginning balance	684
Fair value adjustments	31
Payments	(71)
Ending balance	$ 644
Maximum [Member]
Discount rate used to determine fair value	13.00%
Maximum [Member] \| NBCUniversal Media, LLC [Member]
Discount rate used to determine fair value	13.00%
Minimum [Member]
Discount rate used to determine fair value	5.00%
Minimum [Member] \| NBCUniversal Media, LLC [Member]
Discount rate used to determine fair value	12.00%