Condensed Consolidating Financial Information (Condensed Consolidating Statement of Cash Flows) (Details) - USD ($)
$ in Millions |
12 Months Ended |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
| Operating Activities |
|
|
|
| Net cash provided by operating activities |
$ 24,297
|
$ 21,261
|
$ 19,691
|
| Investing Activities |
|
|
|
| Net transactions with affiliates |
0
|
0
|
0
|
| Capital expenditures |
(9,774)
|
(9,550)
|
(9,135)
|
| Cash paid for intangible assets |
(1,935)
|
(1,605)
|
(1,552)
|
| Acquisitions and construction of real estate properties |
(143)
|
(418)
|
(428)
|
| Construction of Universal Beijing Resort |
(460)
|
(71)
|
(22)
|
| Acquisitions, net of cash acquired |
(38,219)
|
(532)
|
(3,929)
|
| Proceeds from sales of businesses and investments |
141
|
150
|
218
|
| Purchases of investments |
(1,257)
|
(2,292)
|
(1,697)
|
| Deposits |
0
|
0
|
(1,749)
|
| Other |
793
|
785
|
29
|
| Net cash provided by (used in) investing activities |
(50,854)
|
(13,533)
|
(18,265)
|
| Financing Activities |
|
|
|
| Proceeds from (repayments of) short-term borrowings, net |
379
|
(1,905)
|
1,790
|
| Proceeds from borrowings |
44,781
|
11,466
|
9,231
|
| Repurchases and repayments of debt |
(8,798)
|
(6,364)
|
(3,052)
|
| Repurchases of common stock under repurchase program and employee plans |
(5,320)
|
(5,435)
|
(5,352)
|
| Dividends paid |
(3,352)
|
(2,883)
|
(2,601)
|
| Purchase of Universal Studios Japan noncontrolling interests |
0
|
(2,299)
|
0
|
| Issuances of common stock |
0
|
0
|
23
|
| Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock |
(277)
|
(252)
|
(253)
|
| Other |
(273)
|
100
|
(220)
|
| Net cash provided by (used in) financing activities |
27,140
|
(7,572)
|
(434)
|
| Impact of foreign currency on cash, cash equivalents and restricted cash |
(245)
|
0
|
0
|
| Increase (decrease) in cash and cash equivalents and restricted cash |
338
|
156
|
992
|
| Cash, cash equivalents and restricted cash, beginning of year |
3,571
|
3,415
|
2,423
|
| Cash, cash equivalents and restricted cash, end of year |
3,909
|
3,571
|
3,415
|
| Elimination and Consolidation Adjustments [Member] |
|
|
|
| Operating Activities |
|
|
|
| Net cash provided by operating activities |
0
|
0
|
0
|
| Investing Activities |
|
|
|
| Net transactions with affiliates |
0
|
0
|
0
|
| Capital expenditures |
0
|
0
|
0
|
| Cash paid for intangible assets |
0
|
0
|
0
|
| Acquisitions and construction of real estate properties |
0
|
0
|
0
|
| Construction of Universal Beijing Resort |
0
|
0
|
0
|
| Acquisitions, net of cash acquired |
0
|
0
|
0
|
| Proceeds from sales of businesses and investments |
0
|
0
|
0
|
| Purchases of investments |
0
|
0
|
0
|
| Deposits |
0
|
0
|
0
|
| Other |
0
|
0
|
0
|
| Net cash provided by (used in) investing activities |
0
|
0
|
0
|
| Financing Activities |
|
|
|
| Proceeds from (repayments of) short-term borrowings, net |
0
|
0
|
0
|
| Proceeds from borrowings |
0
|
0
|
0
|
| Repurchases and repayments of debt |
0
|
0
|
0
|
| Repurchases of common stock under repurchase program and employee plans |
0
|
0
|
0
|
| Dividends paid |
0
|
0
|
0
|
| Purchase of Universal Studios Japan noncontrolling interests |
0
|
0
|
|
| Issuances of common stock |
0
|
0
|
0
|
| Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock |
0
|
0
|
0
|
| Other |
0
|
0
|
0
|
| Net cash provided by (used in) financing activities |
0
|
0
|
0
|
| Impact of foreign currency on cash, cash equivalents and restricted cash |
0
|
|
|
| Increase (decrease) in cash and cash equivalents and restricted cash |
0
|
0
|
0
|
| Cash, cash equivalents and restricted cash, beginning of year |
0
|
0
|
0
|
| Cash, cash equivalents and restricted cash, end of year |
0
|
0
|
0
|
| Comcast Parent [Member] | Reportable Legal Entities [Member] |
|
|
|
| Operating Activities |
|
|
|
| Net cash provided by operating activities |
(2,245)
|
151
|
349
|
| Investing Activities |
|
|
|
| Net transactions with affiliates |
(26,179)
|
5,578
|
(1,956)
|
| Capital expenditures |
(27)
|
(12)
|
(13)
|
| Cash paid for intangible assets |
(4)
|
(4)
|
(9)
|
| Acquisitions and construction of real estate properties |
(105)
|
(267)
|
(35)
|
| Construction of Universal Beijing Resort |
0
|
0
|
0
|
| Acquisitions, net of cash acquired |
0
|
0
|
0
|
| Proceeds from sales of businesses and investments |
0
|
0
|
0
|
| Purchases of investments |
(126)
|
(70)
|
(40)
|
| Deposits |
0
|
0
|
0
|
| Other |
148
|
101
|
(108)
|
| Net cash provided by (used in) investing activities |
(26,293)
|
5,326
|
(2,161)
|
| Financing Activities |
|
|
|
| Proceeds from (repayments of) short-term borrowings, net |
(902)
|
(837)
|
1,339
|
| Proceeds from borrowings |
44,113
|
5,997
|
9,231
|
| Repurchases and repayments of debt |
(5,737)
|
(2,288)
|
(750)
|
| Repurchases of common stock under repurchase program and employee plans |
(5,320)
|
(5,435)
|
(5,352)
|
| Dividends paid |
(3,352)
|
(2,883)
|
(2,601)
|
| Purchase of Universal Studios Japan noncontrolling interests |
0
|
0
|
|
| Issuances of common stock |
0
|
0
|
23
|
| Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock |
0
|
0
|
0
|
| Other |
(201)
|
(31)
|
(78)
|
| Net cash provided by (used in) financing activities |
28,601
|
(5,477)
|
1,812
|
| Impact of foreign currency on cash, cash equivalents and restricted cash |
(63)
|
|
|
| Increase (decrease) in cash and cash equivalents and restricted cash |
0
|
0
|
0
|
| Cash, cash equivalents and restricted cash, beginning of year |
0
|
0
|
0
|
| Cash, cash equivalents and restricted cash, end of year |
0
|
0
|
0
|
| Subsidiary Issuer [Member] | Reportable Legal Entities [Member] | Comcast Holdings [Member] |
|
|
|
| Operating Activities |
|
|
|
| Net cash provided by operating activities |
126
|
15
|
(336)
|
| Investing Activities |
|
|
|
| Net transactions with affiliates |
(575)
|
(5)
|
336
|
| Capital expenditures |
0
|
0
|
0
|
| Cash paid for intangible assets |
0
|
0
|
0
|
| Acquisitions and construction of real estate properties |
0
|
0
|
0
|
| Construction of Universal Beijing Resort |
0
|
0
|
0
|
| Acquisitions, net of cash acquired |
0
|
0
|
0
|
| Proceeds from sales of businesses and investments |
0
|
0
|
0
|
| Purchases of investments |
0
|
(10)
|
0
|
| Deposits |
0
|
0
|
0
|
| Other |
449
|
0
|
0
|
| Net cash provided by (used in) investing activities |
(126)
|
(15)
|
336
|
| Financing Activities |
|
|
|
| Proceeds from (repayments of) short-term borrowings, net |
0
|
0
|
0
|
| Proceeds from borrowings |
0
|
0
|
0
|
| Repurchases and repayments of debt |
0
|
0
|
0
|
| Repurchases of common stock under repurchase program and employee plans |
0
|
0
|
0
|
| Dividends paid |
0
|
0
|
0
|
| Purchase of Universal Studios Japan noncontrolling interests |
0
|
0
|
|
| Issuances of common stock |
0
|
0
|
0
|
| Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock |
0
|
0
|
0
|
| Other |
0
|
0
|
0
|
| Net cash provided by (used in) financing activities |
0
|
0
|
0
|
| Impact of foreign currency on cash, cash equivalents and restricted cash |
0
|
|
|
| Increase (decrease) in cash and cash equivalents and restricted cash |
0
|
0
|
0
|
| Cash, cash equivalents and restricted cash, beginning of year |
0
|
0
|
0
|
| Cash, cash equivalents and restricted cash, end of year |
0
|
0
|
0
|
| Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | CCCL Parent [Member] |
|
|
|
| Operating Activities |
|
|
|
| Net cash provided by operating activities |
(112)
|
(147)
|
(100)
|
| Investing Activities |
|
|
|
| Net transactions with affiliates |
112
|
757
|
100
|
| Capital expenditures |
0
|
0
|
0
|
| Cash paid for intangible assets |
0
|
0
|
0
|
| Acquisitions and construction of real estate properties |
0
|
0
|
0
|
| Construction of Universal Beijing Resort |
0
|
0
|
0
|
| Acquisitions, net of cash acquired |
0
|
0
|
0
|
| Proceeds from sales of businesses and investments |
0
|
0
|
0
|
| Purchases of investments |
0
|
(60)
|
0
|
| Deposits |
0
|
0
|
0
|
| Other |
0
|
0
|
0
|
| Net cash provided by (used in) investing activities |
112
|
697
|
100
|
| Financing Activities |
|
|
|
| Proceeds from (repayments of) short-term borrowings, net |
0
|
0
|
0
|
| Proceeds from borrowings |
0
|
0
|
0
|
| Repurchases and repayments of debt |
0
|
(550)
|
0
|
| Repurchases of common stock under repurchase program and employee plans |
0
|
0
|
0
|
| Dividends paid |
0
|
0
|
0
|
| Purchase of Universal Studios Japan noncontrolling interests |
0
|
0
|
|
| Issuances of common stock |
0
|
0
|
0
|
| Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock |
0
|
0
|
0
|
| Other |
0
|
0
|
0
|
| Net cash provided by (used in) financing activities |
0
|
(550)
|
0
|
| Impact of foreign currency on cash, cash equivalents and restricted cash |
0
|
|
|
| Increase (decrease) in cash and cash equivalents and restricted cash |
0
|
0
|
0
|
| Cash, cash equivalents and restricted cash, beginning of year |
0
|
0
|
0
|
| Cash, cash equivalents and restricted cash, end of year |
0
|
0
|
0
|
| Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | NBCUniversal Media Parent [Member] |
|
|
|
| Operating Activities |
|
|
|
| Net cash provided by operating activities |
(1,430)
|
(1,439)
|
(1,453)
|
| Investing Activities |
|
|
|
| Net transactions with affiliates |
1,336
|
1,447
|
2,642
|
| Capital expenditures |
0
|
0
|
0
|
| Cash paid for intangible assets |
0
|
0
|
0
|
| Acquisitions and construction of real estate properties |
0
|
0
|
0
|
| Construction of Universal Beijing Resort |
0
|
0
|
0
|
| Acquisitions, net of cash acquired |
0
|
0
|
0
|
| Proceeds from sales of businesses and investments |
68
|
14
|
104
|
| Purchases of investments |
(50)
|
(62)
|
(210)
|
| Deposits |
0
|
0
|
0
|
| Other |
0
|
58
|
(35)
|
| Net cash provided by (used in) investing activities |
1,354
|
1,457
|
2,501
|
| Financing Activities |
|
|
|
| Proceeds from (repayments of) short-term borrowings, net |
0
|
0
|
0
|
| Proceeds from borrowings |
0
|
0
|
0
|
| Repurchases and repayments of debt |
(4)
|
(4)
|
(1,005)
|
| Repurchases of common stock under repurchase program and employee plans |
0
|
0
|
0
|
| Dividends paid |
0
|
0
|
0
|
| Purchase of Universal Studios Japan noncontrolling interests |
0
|
0
|
|
| Issuances of common stock |
0
|
0
|
0
|
| Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock |
0
|
0
|
0
|
| Other |
0
|
0
|
25
|
| Net cash provided by (used in) financing activities |
(4)
|
(4)
|
(980)
|
| Impact of foreign currency on cash, cash equivalents and restricted cash |
0
|
|
|
| Increase (decrease) in cash and cash equivalents and restricted cash |
(80)
|
14
|
68
|
| Cash, cash equivalents and restricted cash, beginning of year |
496
|
482
|
414
|
| Cash, cash equivalents and restricted cash, end of year |
416
|
496
|
482
|
| Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] |
|
|
|
| Operating Activities |
|
|
|
| Net cash provided by operating activities |
27,958
|
22,681
|
21,231
|
| Investing Activities |
|
|
|
| Net transactions with affiliates |
25,306
|
(7,777)
|
(1,122)
|
| Capital expenditures |
(9,747)
|
(9,538)
|
(9,122)
|
| Cash paid for intangible assets |
(1,931)
|
(1,601)
|
(1,543)
|
| Acquisitions and construction of real estate properties |
(38)
|
(151)
|
(393)
|
| Construction of Universal Beijing Resort |
(460)
|
(71)
|
(22)
|
| Acquisitions, net of cash acquired |
(38,219)
|
(532)
|
(3,929)
|
| Proceeds from sales of businesses and investments |
73
|
136
|
114
|
| Purchases of investments |
(1,081)
|
(2,090)
|
(1,447)
|
| Deposits |
0
|
0
|
(1,749)
|
| Other |
196
|
626
|
172
|
| Net cash provided by (used in) investing activities |
(25,901)
|
(20,998)
|
(19,041)
|
| Financing Activities |
|
|
|
| Proceeds from (repayments of) short-term borrowings, net |
1,281
|
(1,068)
|
451
|
| Proceeds from borrowings |
668
|
5,469
|
0
|
| Repurchases and repayments of debt |
(3,057)
|
(3,522)
|
(1,297)
|
| Repurchases of common stock under repurchase program and employee plans |
0
|
0
|
0
|
| Dividends paid |
0
|
0
|
0
|
| Purchase of Universal Studios Japan noncontrolling interests |
0
|
(2,299)
|
|
| Issuances of common stock |
0
|
0
|
0
|
| Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock |
(277)
|
(252)
|
(253)
|
| Other |
(72)
|
131
|
(167)
|
| Net cash provided by (used in) financing activities |
(1,457)
|
(1,541)
|
(1,266)
|
| Impact of foreign currency on cash, cash equivalents and restricted cash |
(182)
|
|
|
| Increase (decrease) in cash and cash equivalents and restricted cash |
418
|
142
|
924
|
| Cash, cash equivalents and restricted cash, beginning of year |
3,075
|
2,933
|
2,009
|
| Cash, cash equivalents and restricted cash, end of year |
$ 3,493
|
$ 3,075
|
$ 2,933
|