Bank Financing and Debt (Details) - USD ($)	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Debt Disclosure [Abstract]
Senior debt (1.95% - 7.875% due 2016 - 2045) (a)	$ 8,166,000,000	$ 8,365,000,000
Obligations under capital leases	83,000,000	83,000,000
Current portion of long-term debt	23,000,000	222,000,000
Total long-term debt, net of current portion	8,226,000,000	8,226,000,000
Total debt	8,249,000,000	8,448,000,000
Net unamortized discount on senior debt	44,000,000	45,000,000
Unamortized deferred financing costs	43,000,000	44,000,000
Increase in carrying value of debt relating to previously settled fair value hedges	13,000,000	14,000,000
Commercial paper	0	$ 0
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity line under credit facility	2,500,000,000.0
Availability under credit facility	2,490,000,000
Amount borrowed under credit facility	$ 0
Revolving Credit Facility [Member] | Maximum Consolidated Leverage Ratio [Member]
Line of Credit Facility [Line Items]
Credit facility covenant description	4.5x
Revolving Credit Facility [Member] | Consolidated Leverage Ratio [Member]
Line of Credit Facility [Line Items]
Credit facility covenant compliance	2.4x
Commercial Paper [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity line under credit facility	$ 2,500,000,000.0