v3.6.0.2
Goodwill and Intangible Assets (Intangible Assets) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Schedule of Indefinite and Finite-Lived Intangible Assets [Line Items]    
Total $ 87,651 $ 86,178
Finite-Lived Intangible Assets [Line Items]    
Accumulated Amortization $ (11,013) (9,868)
Customer Relationships [Member]    
Finite-Lived Intangible Assets [Line Items]    
Weighted-Average Original Useful Life 19 years  
Gross Carrying Amount $ 13,478 13,396
Accumulated Amortization $ (5,110) (4,442)
Software [Member]    
Finite-Lived Intangible Assets [Line Items]    
Weighted-Average Original Useful Life 4 years  
Gross Carrying Amount $ 7,017 6,008
Accumulated Amortization $ (3,997) (3,429)
Cable franchise renewal costs and contractual operating rights [Member]    
Finite-Lived Intangible Assets [Line Items]    
Weighted-Average Original Useful Life 9 years  
Gross Carrying Amount $ 1,460 1,499
Accumulated Amortization $ (800) (849)
Patents and other technology rights [Member]    
Finite-Lived Intangible Assets [Line Items]    
Weighted-Average Original Useful Life 7 years  
Gross Carrying Amount $ 257 409
Accumulated Amortization $ (208) (350)
Other agreements and rights [Member]    
Finite-Lived Intangible Assets [Line Items]    
Weighted-Average Original Useful Life 15 years  
Gross Carrying Amount $ 2,443 1,994
Accumulated Amortization (898) (798)
Franchise Rights [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Gross Carrying Amount 59,364 59,364
Trade Names [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Gross Carrying Amount 2,981 2,857
FCC Licenses [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Gross Carrying Amount 651 651
NBCUniversal Media LLC [Member]    
Schedule of Indefinite and Finite-Lived Intangible Assets [Line Items]    
Total 20,345 19,460
Finite-Lived Intangible Assets [Line Items]    
Accumulated Amortization $ (6,568) (5,654)
NBCUniversal Media LLC [Member] | Customer Relationships [Member]    
Finite-Lived Intangible Assets [Line Items]    
Weighted-Average Original Useful Life 19 years  
Gross Carrying Amount $ 13,173 13,107
Accumulated Amortization $ (4,952) (4,291)
NBCUniversal Media LLC [Member] | Software [Member]    
Finite-Lived Intangible Assets [Line Items]    
Weighted-Average Original Useful Life 5 years  
Gross Carrying Amount $ 1,195 849
Accumulated Amortization $ (563) (431)
NBCUniversal Media LLC [Member] | Other agreements and rights [Member]    
Finite-Lived Intangible Assets [Line Items]    
Weighted-Average Original Useful Life 15 years  
Gross Carrying Amount $ 2,345 1,996
Accumulated Amortization (1,053) (932)
NBCUniversal Media LLC [Member] | Trade Names [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Gross Carrying Amount 2,981 2,857
NBCUniversal Media LLC [Member] | FCC Licenses [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Gross Carrying Amount $ 651 $ 651