Changes in Accumulated Other Comprehensive Income Level 4 (Details) - Reclassifications Out of Accumulated Other Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income tax (benefit) expense	$ 57	$ (351)	$ 31	$ (349)
Amounts reclassified from Accumulated other comprehensive loss, net of tax	4	2	14	3
Gains and Losses on Cash Flow Hedges [Member]
Amount Reclassified From Accumulated Other Comprehensive Loss, before tax	0	1	0	2
Income tax (benefit) expense	0	0	1	0
Amounts reclassified from Accumulated other comprehensive loss, net of tax	0	1	1	2
Defined Benefit Pension Items [Member]
Amortization of prior service cost (benefit)	0	0	1	0
Amortization of Actuarial Losses	5	1	14	1
Income tax (benefit) expense	(1)	0	(2)	0
Amounts reclassified from Accumulated other comprehensive loss, net of tax	$ 4	$ 1	$ 13	$ 1