Pension Plans and Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Severance costs	$ 181	$ 152	$ 160
Multiemployer Plans Funded Status	At least 80 percent
NBCUniversal Media LLC [Member]
Severance costs	$ 113	113	116
Multiemployer Plans Funded Status	At least 80 percent
Pension Benefits [Member]
Multiemployer plan contributions	$ 77	58	59
Contribution to fully fund and settle plan			55
Reclassification adjustment from accumulated other comprehensive income before tax			74
Pension Benefits [Member] \| NBCUniversal Media LLC [Member]
Multiemployer plan contributions	77	58	59
Deferred Compensation Plans [Member]
Cash surrender value of life insurance policies	658	628
Retirement Investment Plans [Member]
Expenses related to retirement investment plans	416	379	324
Retirement Investment Plans [Member] \| NBCUniversal Media LLC [Member]
Expenses related to retirement investment plans	174	165	152
NBCUniversal Qualified Pension Plan [Member]
Contribution to fully fund and settle plan	20
Reclassification adjustment from accumulated other comprehensive income before tax	27
NBCUniversal Qualified Pension Plan [Member] \| NBCUniversal Media LLC [Member]
Benefit obligations in excess of plan assets	67	51
Contribution to fully fund and settle plan	20
Reclassification adjustment from accumulated other comprehensive income before tax	27
Postretirement and Other Benefits [Member]
Multiemployer plan contributions	119	125	98
Postretirement and Other Benefits [Member] \| NBCUniversal Media LLC [Member]
Multiemployer plan contributions	$ 119	$ 125	$ 98

Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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If aggregate disclosures are presented, the aggregate fair value of plan assets for plans with benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

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The amount that relates to an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include (a) making lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and (b) purchasing nonparticipating annuity contracts.

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The amount of the cost recognized during the period for defined contribution plans.

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Amount of contributions made to multiemployer plans by the employer. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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Indicate whether the multiemployer plan is less than 65 percent funded, between 65 and less than 80 percent funded, or at least 80 percent funded. The acceptable values are: (1) "less than 65 percent", (2) "between 65 and less than 80 percent", (3) "at least 80 percent", and (4) "NA". A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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