Amounts Recognized on Balance Sheets Related to Qualified Defined Benefit Pension Plans and Retiree Medical and Life Insurance PlansDisclosure - Amounts Recognized on Balance Sheets Related to Qualified Defined Benefit Pension Plans and Retiree Medical and Life Insurance Plans (Detail) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Accrued postretirement benefit liabilities		$ (11,807)	$ (11,413)
Qualified defined benefit pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension asset		201	204
Accrued postretirement benefit liabilities		(11,807)	(11,413)
Accumulated other comprehensive loss (pre-tax) related to net actuarial losses		19,632	20,794
Accumulated other comprehensive loss (pre-tax) related to prior service (credit) cost		(3,565)	(3,985)
Total	[1]	16,067	16,809
Retiree medical and life insurance plans
Defined Benefit Plan Disclosure [Line Items]
Accrued postretirement benefit liabilities		(1,070)	(1,102)
Accumulated other comprehensive loss (pre-tax) related to net actuarial losses		627	741
Accumulated other comprehensive loss (pre-tax) related to prior service (credit) cost		167	14
Total	[1]	$ 794	$ 755

[1] Accumulated other comprehensive loss related to postretirement benefit plans, after tax, of $11.3 billion and $11.8 billion at December 31, 2015 and 2014 (Note 12) includes $16.1 billion ($10.4 billion after tax) and $16.8 billion ($10.8 billion after tax) for qualified defined benefit pension plans, $794 million ($514 million after tax) and $755 million ($488 million after tax) for retiree medical and life insurance plans and $620 million ($408 million after tax) and $692 million ($460 million after tax) for other plans.