v3.3.1.900
Schedule II Valuation and Qualifying Accounts (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Allowance for Doubtful Accounts [Member]      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at Beginning of Year $ 205 $ 221 $ 198
Additions Charged to Costs and Expenses 166 162 317
Deductions from Reserves 145 178 294
Balance at End of Year 226 205 221
Allowance for Doubtful Accounts [Member] | NBCUniversal Media LLC [Member]      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at Beginning of Year 60 65 46
Additions Charged to Costs and Expenses 27 11 33
Deductions from Reserves 18 16 14
Balance at End of Year 69 60 65
Sales Returns and Allowances [Member]      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at Beginning of Year 359 375 307
Additions Charged to Costs and Expenses 1,236 932 811
Deductions from Reserves 1,122 948 743
Balance at End of Year 473 359 375
Sales Returns and Allowances [Member] | NBCUniversal Media LLC [Member]      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at Beginning of Year 356 372 307
Additions Charged to Costs and Expenses 1,233 930 808
Deductions from Reserves 1,120 946 743
Balance at End of Year 469 356 372
Deferred Tax Valuation Allowance      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at Beginning of Year 375 405 355
Additions Charged to Costs and Expenses 4 33 71
Deductions from Reserves 37 63 21
Balance at End of Year 342 375 405
Deferred Tax Valuation Allowance | NBCUniversal Media LLC [Member]      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at Beginning of Year 87 60 73
Additions Charged to Costs and Expenses 4 33 8
Deductions from Reserves 20 6 21
Balance at End of Year $ 71 $ 87 $ 60