Supplemental Financial Information (Noncash Investing and Financing Activities)(Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Financial Information [Line Items]
Capital expenditures incurred but not yet paid	$ 1,300	$ 1,100	$ 797
Dividends payable	$ 653	$ 612	$ 572
Dividends payable (in dollars per share)	$ 0.275	$ 0.25	$ 0.225
Fair value equity securities settlement		$ 517	$ 3,200
NBCUniversal Media LLC [Member]
Supplemental Financial Information [Line Items]
Capital expenditures incurred but not yet paid	$ 189	287	$ 148
Contribution from member	$ 3,655	$ 252