v3.6.0.2
Schedule II Valuation and Qualifying Accounts (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Allowance for doubtful accounts [Member]      
Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Year $ 226 $ 205 $ 221
Additions Charged to Costs and Expenses 86 166 162
Deductions from Reserves 62 145 178
Balance at End of Year 250 226 205
Allowance for doubtful accounts [Member] | NBCUniversal Media LLC [Member]      
Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Year 69 60 65
Additions Charged to Costs and Expenses 26 27 11
Deductions from Reserves 11 18 16
Balance at End of Year 84 69 60
Allowance for returns and customer incentives [Member]      
Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Year 473 359 375
Additions Charged to Costs and Expenses 1,041 1,236 932
Deductions from Reserves 1,097 1,122 948
Balance at End of Year 417 473 359
Allowance for returns and customer incentives [Member] | NBCUniversal Media LLC [Member]      
Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Year 469 356 372
Additions Charged to Costs and Expenses 1,040 1,233 930
Deductions from Reserves 1,096 1,120 946
Balance at End of Year 413 469 356
Valuation allowance on deferred tax assets [Member]      
Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Year 342 375 405
Additions Charged to Costs and Expenses 23 4 33
Deductions from Reserves 99 37 63
Balance at End of Year 266 342 375
Valuation allowance on deferred tax assets [Member] | NBCUniversal Media LLC [Member]      
Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Year 71 87 60
Additions Charged to Costs and Expenses 23 4 33
Deductions from Reserves 22 20 6
Balance at End of Year $ 72 $ 71 $ 87