Pension and Other Postretirement Benefits (Details) (USD $) In Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Pension Benefit Cost (Credit)
Components of Net Periodic Benefit Costs
Service cost	$ 34		$ 25		$ 97		$ 74
Interest cost	96		79		277		236
Expected return on plan assets	(115)		(90)		(332)		(271)
Amortization of prior service cost	4		3		12		10
Recognized net actuarial loss	49		47		146		141
Curtailments	0	[1]	0	[1]	(2)	[1]	0	[1]
Special Termination Benefits	0	[1]	0	[1]	9	[1]	0	[1]
Net periodic cost (credit)	68		64		207		190
Other Postretirement Benefit Cost (Credit)
Components of Net Periodic Benefit Costs
Service cost	4		2		10		7
Interest cost	13		11		36		33
Expected return on plan assets	(10)		(9)		(30)		(27)
Amortization of prior service cost	(51)		(48)		(151)		(144)
Recognized net actuarial loss	14		15		42		45
Net periodic cost (credit)	$ (30)		$ (29)		$ (93)		$ (86)

[1] Represents costs (credits) incurred related to change in control provision payments to certain executives who were terminated or were expected to be terminated as a result of the merger.