Supplementary Financial Information (Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014
Cash payments related to:
Interest paid (a)	[1]	$ 976	$ 938
Capitalized interest		(8)	(14)
Interest paid (net of capitalized interest) (a)	[1]	968	924
Reorganization items (b)	[2]	114	41
Noncash investing and financing activities:
Construction expenditures (c)	[3]	64	73
Income taxes		26	33
Contribution related to parent stock based compensation		$ 0	$ 2

[1] Net of amounts received under interest rate swap agreements. This amount also includes amounts paid for adequate protection.

[2] Represents cash payments for legal and other consulting services.

[3] Represents end-of-period accruals.