Reconciliation Of Benefit Obligations, Plan Assets, And Unfunded Status (Parenthetical) (Detail) (Qualified Defined Benefit Pension Plans, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Lump-sum settlement payments to former employees	$ 2,094	[1]	$ 1,685	[1]
Benefit obligation released	375
Lump-sum settlement payments
Defined Benefit Plan Disclosure [Line Items]
Lump-sum settlement payments to former employees	$ 310

[1] Benefits paid in 2012 for qualified defined benefit pension plans include $310 million in the form of lump-sum settlement payments to former employees who had not commenced receiving their vested benefit payments. The corresponding benefit obligation that was released was $375 million. The settlement payments had no impact on our 2012 FAS pension expense and CAS pension cost.