Condensed Statements Of Consolidated Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income	$ 118	$ 160	$ 308	$ 367
Other comprehensive income — net of tax effects:
Investment in long-term debt of affiliates — net increase in fair value of securities available for sale (net of tax expense of $103, $30, $147 and $31) (Note 3)	191	55	272	56
Cash flow hedges — Net decrease in fair value of derivatives held by unconsolidated subsidiary (net of tax benefit of $—, $13, $— and $13)	0	(24)	0	(24)
Cash flow hedges — Derivative value net loss related to hedged transactions recognized during the period and reported in equity earnings of unconsolidated subsidiary (net of tax benefit of $—, $—, $1 and $—) (Note 6)	1	0	2	0
Total other comprehensive income	192	31	274	32
Comprehensive income	$ 310	$ 191	$ 582	$ 399