Accumulated Other Comprehensive Income (Loss) (Components Of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss) Net Of Tax [Roll Forward]
Balance, Tax			$ (1,210)
Balance, Net of Tax			(2,032)
Other comprehensive income (loss), before reclassifications, Tax			0
Other comprehensive income (loss), before reclassifications, net of Tax			(71)
Amounts reclassified from accumulated other comprehensive income (loss), Tax			330
Amounts reclassified from accumulated other comprehensive income (loss), net of Tax			210
Other comprehensive loss before tax	(47)	0	(191)	(110)
Net current-period other comprehensive income (loss), Tax	0	0	330	0
Net current-period other comprehensive income (loss), net of Tax			139
Balance, Tax	(880)		(880)
Balance, Net of Tax	(1,893)		(1,893)
Pension and retiree medical liability [Member]
Accumulated Other Comprehensive Income (Loss) Net Of Tax [Roll Forward]
Balance, before Tax			(887)
Other comprehensive income (loss), before reclassifications, before Tax			(17)
Amounts reclassified from accumulated other comprehensive income (loss), before Tax			(125)
Other comprehensive loss before tax			(142)
Balance, before Tax	(1,029)		(1,029)
Net unrealized change on investments [Member]
Accumulated Other Comprehensive Income (Loss) Net Of Tax [Roll Forward]
Balance, before Tax			(2)
Other comprehensive income (loss), before reclassifications, before Tax			0
Amounts reclassified from accumulated other comprehensive income (loss), before Tax			0
Other comprehensive loss before tax			0
Balance, before Tax	(2)		(2)
Derivative financial instruments [Member]
Accumulated Other Comprehensive Income (Loss) Net Of Tax [Roll Forward]
Balance, before Tax			67
Other comprehensive income (loss), before reclassifications, before Tax			(54)
Amounts reclassified from accumulated other comprehensive income (loss), before Tax			5
Other comprehensive loss before tax			(49)
Balance, before Tax	18		18
AA [Member]
Accumulated Other Comprehensive Income (Loss) Net Of Tax [Roll Forward]
Balance, Tax			(1,319)
Balance, Net of Tax			(2,152)
Other comprehensive income (loss), before reclassifications, Tax			0
Other comprehensive income (loss), before reclassifications, net of Tax			(69)
Amounts reclassified from accumulated other comprehensive income (loss), Tax			328
Amounts reclassified from accumulated other comprehensive income (loss), net of Tax			209
Other comprehensive loss before tax	(46)	(3)	(188)	(113)
Net current-period other comprehensive income (loss), Tax	0	0	328	0
Net current-period other comprehensive income (loss), net of Tax			140
Balance, Tax	(991)		(991)
Balance, Net of Tax	(2,012)		(2,012)
AA [Member] | Pension and retiree medical liability [Member]
Accumulated Other Comprehensive Income (Loss) Net Of Tax [Roll Forward]
Balance, before Tax			(899)
Other comprehensive income (loss), before reclassifications, before Tax			(17)
Amounts reclassified from accumulated other comprehensive income (loss), before Tax			(122)
Other comprehensive loss before tax			(139)
Balance, before Tax	(1,038)		(1,038)
AA [Member] | Net unrealized change on investments [Member]
Accumulated Other Comprehensive Income (Loss) Net Of Tax [Roll Forward]
Balance, before Tax			1
Other comprehensive income (loss), before reclassifications, before Tax			0
Amounts reclassified from accumulated other comprehensive income (loss), before Tax			(2)
Other comprehensive loss before tax			(2)
Balance, before Tax	(1)		(1)
AA [Member] | Derivative financial instruments [Member]
Accumulated Other Comprehensive Income (Loss) Net Of Tax [Roll Forward]
Balance, before Tax			65
Other comprehensive income (loss), before reclassifications, before Tax			(52)
Amounts reclassified from accumulated other comprehensive income (loss), before Tax			5
Other comprehensive loss before tax			(47)
Balance, before Tax	$ 18		$ 18