Supplemental Financial Information (Cash Payments for Interest and Income Taxes)(Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest	$ 2,389us-gaap_InterestPaidNet	$ 2,355us-gaap_InterestPaidNet	$ 2,314us-gaap_InterestPaidNet
Income taxes	3,668us-gaap_IncomeTaxesPaidNet	3,946us-gaap_IncomeTaxesPaidNet	2,841us-gaap_IncomeTaxesPaidNet
NBCUniversal Media, LLC [Member]
Interest	485	462	461
Income taxes	$ 174	$ 205	$ 169

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4297-108586

Name:	us-gaap_IncomeTaxesPaidNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration