v3.4.0.3
Condensed Consolidating Financial Information (Condensed Consolidating Statement of Cash Flows) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Operating Activities    
Net cash provided by (used in) operating activities $ 5,110 $ 5,245
Investing Activities    
Net transactions with affiliates 0 0
Capital expenditures (1,885) (1,726)
Cash paid for intangible assets (378) (273)
Acquisitions and construction of real estate properties (140) (24)
Acquisitions, net of cash acquired (24) 0
Proceeds from sales of businesses and investments 110 180
Purchases of investments (448) (32)
Other 56 181
Net cash provided by (used in) investing activities (2,709) (1,694)
Financing Activities    
Proceeds from (repayments of) short-term borrowings, net (538) (150)
Proceeds from borrowings 3,323 0
Repurchases and repayments of debt (48) (909)
Repurchases and retirements of common stock (1,249) (2,000)
Dividends paid (611) (572)
Issuances of common stock 12 28
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock (77) (62)
Other 120 141
Net cash provided by (used in) financing activities 932 (3,524)
Increase (decrease) in cash and cash equivalents 3,333 27
Cash and cash equivalents, beginning of period 2,295 3,910
Cash and cash equivalents, end of period 5,628 3,937
Elimination and Consolidation Adjustments [Member]    
Operating Activities    
Net cash provided by (used in) operating activities 0 0
Investing Activities    
Net transactions with affiliates 0 0
Capital expenditures 0 0
Cash paid for intangible assets 0 0
Acquisitions and construction of real estate properties 0 0
Acquisitions, net of cash acquired 0 0
Proceeds from sales of businesses and investments 0 0
Purchases of investments 0 0
Other 0 0
Net cash provided by (used in) investing activities 0 0
Financing Activities    
Proceeds from (repayments of) short-term borrowings, net 0 0
Proceeds from borrowings 0 0
Repurchases and repayments of debt 0 0
Repurchases and retirements of common stock 0 0
Dividends paid 0 0
Issuances of common stock 0 0
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock 0 0
Other 0 0
Net cash provided by (used in) financing activities 0 0
Increase (decrease) in cash and cash equivalents 0 0
Cash and cash equivalents, beginning of period 0 0
Cash and cash equivalents, end of period 0 0
Comcast Parent [Member]    
Operating Activities    
Net cash provided by (used in) operating activities (490) (294)
Investing Activities    
Net transactions with affiliates (679) 3,609
Capital expenditures (3) (6)
Cash paid for intangible assets 0 0
Acquisitions and construction of real estate properties 0 0
Acquisitions, net of cash acquired 0 0
Proceeds from sales of businesses and investments 0 0
Purchases of investments (7) 0
Other 7 0
Net cash provided by (used in) investing activities (682) 3,603
Financing Activities    
Proceeds from (repayments of) short-term borrowings, net (400) 0
Proceeds from borrowings 3,323 0
Repurchases and repayments of debt 0 (900)
Repurchases and retirements of common stock (1,249) (2,000)
Dividends paid (611) (572)
Issuances of common stock 12 28
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock 0 0
Other 97 135
Net cash provided by (used in) financing activities 1,172 (3,309)
Increase (decrease) in cash and cash equivalents 0 0
Cash and cash equivalents, beginning of period 0 0
Cash and cash equivalents, end of period 0 0
Comcast Holdings [Member]    
Operating Activities    
Net cash provided by (used in) operating activities 0 (1)
Investing Activities    
Net transactions with affiliates 0 1
Capital expenditures 0 0
Cash paid for intangible assets 0 0
Acquisitions and construction of real estate properties 0 0
Acquisitions, net of cash acquired 0 0
Proceeds from sales of businesses and investments 0 0
Purchases of investments 0 0
Other 0 0
Net cash provided by (used in) investing activities 0 1
Financing Activities    
Proceeds from (repayments of) short-term borrowings, net 0 0
Proceeds from borrowings 0 0
Repurchases and repayments of debt 0 0
Repurchases and retirements of common stock 0 0
Dividends paid 0 0
Issuances of common stock 0 0
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock 0 0
Other 0 0
Net cash provided by (used in) financing activities 0 0
Increase (decrease) in cash and cash equivalents 0 0
Cash and cash equivalents, beginning of period 0 0
Cash and cash equivalents, end of period 0 0
CCCL Parent [Member]    
Operating Activities    
Net cash provided by (used in) operating activities 78 34
Investing Activities    
Net transactions with affiliates (78) (34)
Capital expenditures 0 0
Cash paid for intangible assets 0 0
Acquisitions and construction of real estate properties 0 0
Acquisitions, net of cash acquired 0 0
Proceeds from sales of businesses and investments 0 0
Purchases of investments 0 0
Other 0 0
Net cash provided by (used in) investing activities (78) (34)
Financing Activities    
Proceeds from (repayments of) short-term borrowings, net 0 0
Proceeds from borrowings 0 0
Repurchases and repayments of debt 0 0
Repurchases and retirements of common stock 0 0
Dividends paid 0 0
Issuances of common stock 0 0
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock 0 0
Other 0 0
Net cash provided by (used in) financing activities 0 0
Increase (decrease) in cash and cash equivalents 0 0
Cash and cash equivalents, beginning of period 0 0
Cash and cash equivalents, end of period 0 0
NBCUniversal Media Parent [Member]    
Operating Activities    
Net cash provided by (used in) operating activities (391) (361)
Investing Activities    
Net transactions with affiliates 63 321
Capital expenditures 0 0
Cash paid for intangible assets 0 0
Acquisitions and construction of real estate properties 0 0
Acquisitions, net of cash acquired 0 0
Proceeds from sales of businesses and investments 101 0
Purchases of investments 0 0
Other (5) (5)
Net cash provided by (used in) investing activities 159 316
Financing Activities    
Proceeds from (repayments of) short-term borrowings, net 0 0
Proceeds from borrowings 0 0
Repurchases and repayments of debt (4) (1)
Repurchases and retirements of common stock 0 0
Dividends paid 0 0
Issuances of common stock 0 0
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock 0 0
Other 0 0
Net cash provided by (used in) financing activities (4) (1)
Increase (decrease) in cash and cash equivalents (236) (46)
Cash and cash equivalents, beginning of period 414 385
Cash and cash equivalents, end of period 178 339
Comcast Non-Guarantor Subsidiaries [Member]    
Operating Activities    
Net cash provided by (used in) operating activities 5,913 5,867
Investing Activities    
Net transactions with affiliates 694 (3,897)
Capital expenditures (1,882) (1,720)
Cash paid for intangible assets (378) (273)
Acquisitions and construction of real estate properties (140) (24)
Acquisitions, net of cash acquired (24) 0
Proceeds from sales of businesses and investments 9 180
Purchases of investments (441) (32)
Other 54 186
Net cash provided by (used in) investing activities (2,108) (5,580)
Financing Activities    
Proceeds from (repayments of) short-term borrowings, net (138) (150)
Proceeds from borrowings 0 0
Repurchases and repayments of debt (44) (8)
Repurchases and retirements of common stock 0 0
Dividends paid 0 0
Issuances of common stock 0 0
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock (77) (62)
Other 23 6
Net cash provided by (used in) financing activities (236) (214)
Increase (decrease) in cash and cash equivalents 3,569 73
Cash and cash equivalents, beginning of period 1,881 3,525
Cash and cash equivalents, end of period $ 5,450 $ 3,598