Borrowings Borrowings (Details) (USD $)	0 Months Ended		3 Months Ended	9 Months Ended						9 Months Ended
	Aug. 22, 2014	Aug. 08, 2014	Sep. 30, 2014	Sep. 30, 2014	Aug. 07, 2014 Unsecured Senior Notes 5.75 Percent Due in 2041 [Member]	Aug. 07, 2014 Unsecured Senior Notes 6.125 Percent Due in 2039 [Member]	Aug. 07, 2014 Unsecured Senior Notes 6.25 Percent Due in 2027 [Member]	Aug. 07, 2014 Unsecured Senior Notes 3.375 Percent Due in 2024 [Member]	Aug. 07, 2014 Unsecured Senior Notes 2.250 Percent Due in 2019 [Member]	Sep. 30, 2014 Unsecured Senior Notes 6.25 Percent Due in 2027 and 6.125 Percent Due in 2039 and 5.75 Percent Due in 2041 and 5.75 Percent Due in 2017 [Member]	Aug. 07, 2014 Unsecured Senior Notes 5.75 Percent Due in 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount								$ 650,000,000	$ 850,000,000
Debt Instrument, Interest Rate, Stated Percentage					5.75%	6.125%	6.25%	3.375%	2.25%		5.75%
Proceeds from Issuance of Senior Long-term Debt		1,500,000,000
Debt tender offer amount, maximum	2,000,000,000.0	1,500,000,000.0
Extinguishment of Debt Tender Premium										490,000,000
Extinguishment of Debt Write off of Unamortized Deferred Financing Charges										26,000,000
Extinguishment of Debt Tender Fees										5,000,000
Loss on Extinguishment of Debt			$ 521,000,000	$ 521,000,000						$ 521,000,000