Film and Television Costs (Narrative)(Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Film And Television Cost [Line Items]
Amortization of completed film and television production expected to be amortized during the next fiscal year	$ 1,900
Expected amortization percentage of released and unamortized film and television costs during the next three fiscal years	88.00%
Remaining unamortized costs of acquired film and television libraries	$ 596
Expected amortization percentage of unamortized acquired film and television library costs during the next three fiscal years	45.00%
Maximum [Member]
Film And Television Cost [Line Items]
Amortization period of acquired film and television library costs	20 years
NBCUniversal Media LLC [Member]
Film And Television Cost [Line Items]
Amortization of completed film and television production expected to be amortized during the next fiscal year	$ 1,900
Expected amortization percentage of released and unamortized film and television costs during the next three fiscal years	88.00%
Remaining unamortized costs of acquired film and television libraries	$ 596
Expected amortization percentage of unamortized acquired film and television library costs during the next three fiscal years	45.00%
NBCUniversal Media LLC [Member] | Maximum [Member]
Film And Television Cost [Line Items]
Amortization period of acquired film and television library costs	20 years
Adjustments To Capitalized Film And Stage Play Production Costs [Member]
Film And Television Cost [Line Items]
Adjustments to capitalized film and stage play production costs	$ 14	$ 42	$ 26
Adjustments To Capitalized Film And Stage Play Production Costs [Member] | NBCUniversal Media LLC [Member]
Film And Television Cost [Line Items]
Adjustments to capitalized film and stage play production costs	$ 14	$ 42	$ 26