Supplementary Financial Information (Interest Expense and Related Charges) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Supplementary Financial Information [Abstract]
Interest paid/accrued (including net amounts settled/accrued under interest rate swaps)	$ 688	$ 647	$ 2,042	$ 1,938
Interest related to pushed down debt	1	19	5	57
Interest payable with additional toggle notes (Note 5)	0	47	0	136
Unrealized mark-to-market net (gain) loss on interest rate swaps	(413)	20	(899)	16
Amortization of interest rate swap losses at dedesignation of hedge accounting	2	2	6	7
Amortization of fair value debt discounts resulting from purchase accounting	3	3	8	8
Amortization of debt issuance, amendment and extension costs and discounts	64	45	195	137
Capitalized interest	(5)	(11)	(19)	(31)
Total interest expense and related charges	$ 340	$ 772	$ 1,338	$ 2,268