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Condensed Consolidating Financial Information (Condensed Consolidating Statement of Income) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017
Revenue: |  |  |  |
Revenue | $ 21,735 | $ 21,286 | $ 44,526 | $ 41,873
Costs and Expenses: |  |  |  |
Programming and production | 6,300 | 6,330 | 13,729 | 12,391
Other operating and administrative | 6,365 | 6,168 | 12,879 | 12,107
Advertising, marketing and promotion | 1,653 | 1,713 | 3,257 | 3,290
Depreciation | 2,021 | 1,970 | 4,032 | 3,885
Amortization | 582 | 537 | 1,170 | 1,090
Other operating gains | (200) | 0 | (200) | 0
Total costs and expenses | 16,721 | 16,718 | 34,867 | 32,763
Operating income | 5,014 | 4,568 | 9,659 | 9,110
Interest expense | (806) | (758) | (1,583) | (1,513)
Investment and other income (loss), net | 77 | 99 | 203 | 229
Income before income taxes | 4,285 | 3,909 | 8,279 | 7,826
Income tax expense | (1,077) | (1,367) | (1,895) | (2,629)
Net income | 3,208 | 2,542 | 6,384 | 5,197
Less: Net income (loss) attributable to noncontrolling interests and redeemable subsidiary preferred stock | (8) | 21 | 50 | 103
Net income attributable to Comcast Corporation | 3,216 | 2,521 | 6,334 | 5,094
Comprehensive income (loss) attributable to Comcast Corporation | 3,069 | 2,413 | 6,340 | 5,230
Elimination and Consolidation Adjustments [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | (591) | (558) | (1,169) | (1,103)
Costs and Expenses: |  |  |  |
Programming and production | 0 | 0 | 0 | 0
Other operating and administrative | (591) | (558) | (1,169) | (1,103)
Advertising, marketing and promotion | 0 | 0 | 0 | 0
Depreciation | 0 | 0 | 0 | 0
Amortization | 0 | 0 | 0 | 0
Other operating gains | 0 | 0 | 0 | 0
Total costs and expenses | (591) | (558) | (1,169) | (1,103)
Operating income | 0 | 0 | 0 | 0
Interest expense | 0 | 0 | 0 | 0
Investment and other income (loss), net | (13,012) | (10,684) | (26,081) | (21,316)
Income before income taxes | (13,012) | (10,684) | (26,081) | (21,316)
Income tax expense | 0 | 0 | 0 | 0
Net income | (13,012) | (10,684) | (26,081) | (21,316)
Less: Net income (loss) attributable to noncontrolling interests and redeemable subsidiary preferred stock | 0 | 0 | 0 | 0
Net income attributable to Comcast Corporation | (13,012) | (10,684) | (26,081) | (21,316)
Comprehensive income (loss) attributable to Comcast Corporation | (12,459) | (10,250) | (26,104) | (21,383)
Comcast Parent [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 298 | 281 | 590 | 556
Costs and Expenses: |  |  |  |
Programming and production | 0 | 0 | 0 | 0
Other operating and administrative | 190 | 200 | 418 | 370
Advertising, marketing and promotion | 0 | 0 | 0 | 0
Depreciation | 11 | 7 | 22 | 14
Amortization | 2 | 1 | 3 | 3
Other operating gains | 0 | 0 | 0 | 0
Total costs and expenses | 203 | 208 | 443 | 387
Operating income | 95 | 73 | 147 | 169
Interest expense | (578) | (531) | (1,139) | (1,048)
Investment and other income (loss), net | 3,597 | 2,819 | 7,117 | 5,666
Income before income taxes | 3,114 | 2,361 | 6,125 | 4,787
Income tax expense | 102 | 160 | 209 | 307
Net income | 3,216 | 2,521 | 6,334 | 5,094
Less: Net income (loss) attributable to noncontrolling interests and redeemable subsidiary preferred stock | 0 | 0 | 0 | 0
Net income attributable to Comcast Corporation | 3,216 | 2,521 | 6,334 | 5,094
Comprehensive income (loss) attributable to Comcast Corporation | 3,069 | 2,413 | 6,340 | 5,230
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 21,735 | 21,286 | 44,526 | 41,873
Costs and Expenses: |  |  |  |
Programming and production | 6,300 | 6,330 | 13,729 | 12,391
Other operating and administrative | 6,249 | 5,988 | 12,509 | 11,726
Advertising, marketing and promotion | 1,653 | 1,713 | 3,257 | 3,290
Depreciation | 2,010 | 1,963 | 4,010 | 3,871
Amortization | 580 | 536 | 1,167 | 1,087
Other operating gains | (200) | 0 | (200) | 0
Total costs and expenses | 16,592 | 16,530 | 34,472 | 32,365
Operating income | 5,143 | 4,756 | 10,054 | 9,508
Interest expense | (64) | (57) | (124) | (120)
Investment and other income (loss), net | 1,324 | 1,352 | 2,912 | 2,631
Income before income taxes | 6,403 | 6,051 | 12,842 | 12,019
Income tax expense | (1,185) | (1,530) | (2,114) | (2,948)
Net income | 5,218 | 4,521 | 10,728 | 9,071
Less: Net income (loss) attributable to noncontrolling interests and redeemable subsidiary preferred stock | (8) | 21 | 50 | 103
Net income attributable to Comcast Corporation | 5,226 | 4,500 | 10,678 | 8,968
Comprehensive income (loss) attributable to Comcast Corporation | 4,903 | 4,257 | 10,694 | 8,969
Comcast Holdings [Member] | Subsidiary Issuer [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 0 | 0 | 0 | 0
Costs and Expenses: |  |  |  |
Programming and production | 0 | 0 | 0 | 0
Other operating and administrative | 0 | 0 | 0 | 0
Advertising, marketing and promotion | 0 | 0 | 0 | 0
Depreciation | 0 | 0 | 0 | 0
Amortization | 0 | 0 | 0 | 0
Other operating gains | 0 | 0 | 0 | 0
Total costs and expenses | 0 | 0 | 0 | 0
Operating income | 0 | 0 | 0 | 0
Interest expense | (3) | (3) | (6) | (6)
Investment and other income (loss), net | 3,580 | 2,642 | 6,899 | 5,328
Income before income taxes | 3,577 | 2,639 | 6,893 | 5,322
Income tax expense | 1 | (7) | 1 | (16)
Net income | 3,578 | 2,632 | 6,894 | 5,306
Less: Net income (loss) attributable to noncontrolling interests and redeemable subsidiary preferred stock | 0 | 0 | 0 | 0
Net income attributable to Comcast Corporation | 3,578 | 2,632 | 6,894 | 5,306
Comprehensive income (loss) attributable to Comcast Corporation | 3,527 | 2,596 | 6,896 | 5,320
CCCL Parent [Member] | Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 293 | 277 | 579 | 547
Costs and Expenses: |  |  |  |
Programming and production | 0 | 0 | 0 | 0
Other operating and administrative | 293 | 277 | 579 | 547
Advertising, marketing and promotion | 0 | 0 | 0 | 0
Depreciation | 0 | 0 | 0 | 0
Amortization | 0 | 0 | 0 | 0
Other operating gains | 0 | 0 | 0 | 0
Total costs and expenses | 293 | 277 | 579 | 547
Operating income | 0 | 0 | 0 | 0
Interest expense | (48) | (51) | (95) | (111)
Investment and other income (loss), net | 2,999 | 2,306 | 5,825 | 4,633
Income before income taxes | 2,951 | 2,255 | 5,730 | 4,522
Income tax expense | 10 | 18 | 19 | 39
Net income | 2,961 | 2,273 | 5,749 | 4,561
Less: Net income (loss) attributable to noncontrolling interests and redeemable subsidiary preferred stock | 0 | 0 | 0 | 0
Net income attributable to Comcast Corporation | 2,961 | 2,273 | 5,749 | 4,561
Comprehensive income (loss) attributable to Comcast Corporation | 2,960 | 2,274 | 5,749 | 4,563
NBCUniversal Media Parent [Member] | Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 0 | 0 | 0 | 0
Costs and Expenses: |  |  |  |
Programming and production | 0 | 0 | 0 | 0
Other operating and administrative | 224 | 261 | 542 | 567
Advertising, marketing and promotion | 0 | 0 | 0 | 0
Depreciation | 0 | 0 | 0 | 0
Amortization | 0 | 0 | 0 | 0
Other operating gains | 0 | 0 | 0 | 0
Total costs and expenses | 224 | 261 | 542 | 567
Operating income | (224) | (261) | (542) | (567)
Interest expense | (113) | (116) | (219) | (228)
Investment and other income (loss), net | 1,589 | 1,664 | 3,531 | 3,287
Income before income taxes | 1,252 | 1,287 | 2,770 | 2,492
Income tax expense | (5) | (8) | (10) | (11)
Net income | 1,247 | 1,279 | 2,760 | 2,481
Less: Net income (loss) attributable to noncontrolling interests and redeemable subsidiary preferred stock | 0 | 0 | 0 | 0
Net income attributable to Comcast Corporation | 1,247 | 1,279 | 2,760 | 2,481
Comprehensive income (loss) attributable to Comcast Corporation | 1,069 | 1,123 | 2,765 | 2,531
Service [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 21,735 | 21,286 | 44,526 | 41,873
Service [Member] | Elimination and Consolidation Adjustments [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 0 | 0 | 0 | 0
Service [Member] | Comcast Parent [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 0 | 0 | 0 | 0
Service [Member] | Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 21,735 | 21,286 | 44,526 | 41,873
Service [Member] | Comcast Holdings [Member] | Subsidiary Issuer [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 0 | 0 | 0 | 0
Service [Member] | CCCL Parent [Member] | Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 0 | 0 | 0 | 0
Service [Member] | NBCUniversal Media Parent [Member] | Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 0 | 0 | 0 | 0
Management Fee [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 0 | 0 | 0 | 0
Management Fee [Member] | Elimination and Consolidation Adjustments [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | (591) | (558) | (1,169) | (1,103)
Management Fee [Member] | Comcast Parent [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 298 | 281 | 590 | 556
Management Fee [Member] | Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 0 | 0 | 0 | 0
Management Fee [Member] | Comcast Holdings [Member] | Subsidiary Issuer [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 0 | 0 | 0 | 0
Management Fee [Member] | CCCL Parent [Member] | Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | 293 | 277 | 579 | 547
Management Fee [Member] | NBCUniversal Media Parent [Member] | Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] |  |  |  |
Revenue: |  |  |  |
Revenue | $ 0 | $ 0 | $ 0 | $ 0

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