Related Party Transactions - Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Millions |
Sep. 30, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Receivables, net | $ 6,527 | $ 6,321 |
| Accounts payable and accrued expenses related to trade creditors | 5,996 | 5,638 |
| Accrued expenses and other current liabilities | 5,455 | 5,293 |
| Other noncurrent liabilities | 10,694 | 10,819 |
| NBCUniversal Media, LLC [Member] | ||
| Receivables, net | 5,056 | 4,842 |
| Note receivable from Comcast | 77 | 0 |
| Accounts payable and accrued expenses related to trade creditors | 1,473 | 1,388 |
| Accrued expenses and other current liabilities | 1,609 | 1,422 |
| Note payable to Comcast | 0 | 865 |
| Other noncurrent liabilities | 3,834 | 3,722 |
| Transactions With Comcast And Consolidated Subsidiaries [Member] | NBCUniversal Media, LLC [Member] | ||
| Receivables, net | 236 | 229 |
| Note receivable from Comcast | 77 | 0 |
| Accounts payable and accrued expenses related to trade creditors | 58 | 47 |
| Accrued expenses and other current liabilities | 43 | 8 |
| Note payable to Comcast | 0 | 865 |
| Other noncurrent liabilities | $ 383 | $ 383 |