v2.4.0.8

Investments (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2014
Investment Summary |
|  |  | September 30, |  | December 31,
(in millions) |  | 2014 |  | 2013
Fair Value Method | $ | 588 | $ | 4,345
Equity Method: |  |  |  |
| The Weather Channel |  | 333 |  | 333
| Hulu |  | 188 |  | 187
| Other |  | 503 |  | 469
|  |  | 1,024 |  | 989
Cost Method: |  |  |  |
| AirTouch |  | 1,564 |  | 1,553
| Other |  | 484 |  | 456
|  |  | 2,048 |  | 2,009
Total investments |  | 3,660 |  | 7,343
Less: Current investments |  | 531 |  | 3,573
Noncurrent investments | $ | 3,129 | $ | 3,770
Investment Income (Loss), Net |
Investment Income (Loss), Net
|  | Three Months Ended |  | Nine Months Ended
|  | September 30 |  | September 30
(in millions) | 2014 | 2013 |  | 2014 | 2013
Gains on sales and exchanges of investments, net | $ | 3 | $ | 445 |  | $ | 176 | $ | 483
Investment impairment losses |  | (6) |  | (12) |  |  | (30) |  | (25)
Unrealized gains (losses) on securities underlying prepaid |  |  |  |  |  |  |  |  |
| forward sale agreements |  | 15 |  | 345 |  |  | (13) |  | 1,197
Mark to market adjustments on derivative component of prepaid |  |  |  |  |  |  |  |  |
| forward sale agreements and indexed debt instruments |  | (13) |  | (348) |  |  | 19 |  | (1,189)
Interest and dividend income |  | 29 |  | 28 |  |  | 85 |  | 84
Other, net |  | (7) |  | 6 |  |  | 17 |  | (1)
Investment income (loss), net | $ | 21 | $ | 464 |  | $ | 254 | $ | 549
Prepaid Forward Sale Agreements |
Prepaid Forward Sale Agreements
|  | September 30, | December 31,
(in millions) | 2014 | 2013
Assets: |  |  |  |
| Fair value equity securities held as collateral | $ | 444 | $ | 3,959
Liabilities: |  |  |  |
| Obligations under prepaid forward sale agreements | $ | 117 | $ | 811
| Derivative component of prepaid forward sale agreements |  | 277 |  | 2,800
Total liabilities | $ | 394 | $ | 3,611
NBCUniversal Media, LLC [Member] |
Investment Summary |
|  |  | September 30, |  | December 31,
(in millions) |  | 2014 |  | 2013
Fair Value Method | $ | 16 | $ | 11
Equity Method: |  |  |  |
| The Weather Channel |  | 333 |  | 333
| Hulu |  | 188 |  | 187
| Other |  | 347 |  | 332
|  |  | 868 |  | 852
Cost Method |  | 28 |  | 21
Total investments |  | 912 |  | 884
Less: Current investments |  | 5 |  | -
Noncurrent Investments | $ | 907 | $ | 884

X
- Definition Components of Investment Income (Loss), Net + References No definition available. + Details
Name: | cmcsa_ComponentsOfInvestmentIncomeLossNetTableTextBlock
Namespace Prefix: | cmcsa_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of equity securities held as collateral related to obligations under prepaid forward sale agreements. + References No definition available. + Details
Name: | cmcsa_PrepaidForwardSaleAgreementsTableTextBlock
Namespace Prefix: | cmcsa_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the summary of investment holdings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-12C) -URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611225-123010 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12C -Article 12 + Details
Name: | us-gaap_SummaryInvestmentHoldingsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration