Additional Financial Information Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Comprehensive Income (loss) Adjustments
Net income (loss)	$ (68)	$ 53	$ (127)	$ 111
Reclassifications included in net income (loss): Gross
Accumulated actuarial losses of benefit plans	(11)	(2)	(11)	(2)
Amortization of actuarial losses	0	0	1	0
Settlement losses	0	2	0	2
Total reclassifications included in net income (loss)	0	2	1	2
Adjustments for pension and other post-employment benefits	(11)	0	(10)	0
Reclassifications included in net income (loss): Taxes
Accumulated actuarial losses of benefit plans	4	1	4	1
Amortization of actuarial losses	0	0	0	0
Settlement losses	0	(1)	0	(1)
Total reclassifications included in net income (loss)	0	(1)	0	(1)
Adjustments for pension and other post-employment benefits	4	0	4	0
Reclassifications included in net income (loss): Net
Accumulated actuarial losses of benefit plans	(7)	(1)	(7)	(1)
Amortization of actuarial losses	0	0	1	0
Settlement losses	0	1	0	1
Total reclassifications included in net income (loss)	0	1	1	1
Adjustments for pension and other post-employment benefits	(7)	0	(6)	0
Amortization of prior service cost and unrecognized net loss	(75)	53	(133)	111
Changes in accumulated other comprehensive income, Gross
Accumulated other comprehensive income at the beginning of the period			(47)
Adjustments for pension and other post-employment benefits, net of amortization			(10)
Accumulated other comprehensive income at the end of the period	(57)		(57)
Changes in accumulated other comprehensive income, Taxes
Accumulated other comprehensive income at the beginning of the period			3
Adjustments for pension and other post-employment benefits, net of amortization			4
Accumulated other comprehensive income at the end of the period	7		7
Changes in accumulated other comprehensive income Net
Accumulated other comprehensive income at the beginning of the period			(44)
Adjustments for pension and other post-employment benefits, net of amortization			(6)
Accumulated other comprehensive income at the end of the period	$ (50)		$ (50)