Condensed Consolidated Statements Of Comprehensive Income (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Unrealized Gains (Losses) on Available-for-Sale Securities, tax	$ (3)	$ (27)
Unrealized Gains (Losses) on Cash Flow Hedges, tax	(2)	2
Pension/OPEB adjustment, tax	(2)	(7)
Power [Member]
Unrealized Gains (Losses) on Available-for-Sale Securities, tax	(2)	(27)
Unrealized Gains (Losses) on Cash Flow Hedges, tax	(1)	2
Pension/OPEB adjustment, tax	$ (2)	$ (5)