Qualified Defined Benefit Pension Plans and Retiree Medical and Life Insurance Plans by Asset Category (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	$ 34,931		$ 32,888
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Cash and cash equivalents	2,176	[1]	2,465	[1]
U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	5,368	[1]	3,931	[1]
International equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	5,008	[1]	3,389	[1]
Commingled equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	6,037	[1]	3,943	[1]
Corporate debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	2,986	[1]	1,106	[1]
U.S. Government securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	6,553	[1]	12,013	[1]
U.S. Government-sponsored enterprise securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	1,451	[1]	239	[1]
Other fixed income investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	1,388	[1]	1,225	[1]
Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	2,601		2,461
Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	601		529
Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	551		806
Commodities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	156	[1]	736	[1]
Total excluding receivables
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	34,876		32,843
Receivables, net
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	55		45
Fair value, inputs, level 1 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Cash and cash equivalents	2,176	[1]	2,465	[1]
Fair value, inputs, level 1 | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	5,274	[1]	3,871	[1]
Fair value, inputs, level 1 | International equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	4,912	[1]	3,363	[1]
Fair value, inputs, level 1 | Commingled equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	1,212	[1]	980	[1]
Fair value, inputs, level 1 | Commodities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	156	[1]	735	[1]
Fair value, inputs, level 1 | Total excluding receivables
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	13,730		11,414
Fair value, inputs, level 2 | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	94	[1]	50	[1]
Fair value, inputs, level 2 | International equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	89	[1]	15	[1]
Fair value, inputs, level 2 | Commingled equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	4,825	[1]	2,963	[1]
Fair value, inputs, level 2 | Corporate debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	2,943	[1]	1,045	[1]
Fair value, inputs, level 2 | U.S. Government securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	6,553	[1]	12,013	[1]
Fair value, inputs, level 2 | U.S. Government-sponsored enterprise securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	1,451	[1]	239	[1]
Fair value, inputs, level 2 | Other fixed income investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	1,293	[1]	1,176	[1]
Fair value, inputs, level 2 | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	29		25
Fair value, inputs, level 2 | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	46
Fair value, inputs, level 2 | Commodities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year			1	[1]
Fair value, inputs, level 2 | Total excluding receivables
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	17,323		17,527
Fair value, inputs, level 3 | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year			10	[1]
Fair value, inputs, level 3 | International equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	7	[1]	11	[1]
Fair value, inputs, level 3 | Corporate debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	43	[1]	61	[1]
Fair value, inputs, level 3 | Other fixed income investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	95	[1]	49	[1]
Fair value, inputs, level 3 | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	2,601		2,461
Fair value, inputs, level 3 | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	572		504
Fair value, inputs, level 3 | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	505		806
Fair value, inputs, level 3 | Total excluding receivables
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	$ 3,823		$ 3,902

[1] Cash and cash equivalents, equity securities, fixed income securities, and commodities included derivative assets and liabilities whose fair values were not material as of December 31, 2013 and 2012. LMIMCo's investment policies restrict the use of derivatives to either establish long exposures for purposes of expediency or capital efficiency, or to hedge risks to the extent of a plan's current exposure to such risks. Most derivative transactions are settled on a daily basis. In addition, we corrected the classification of $980 million of other fixed income investments and $118 million of commingled equity funds as of December 31, 2012, which were reclassified from cash and cash equivalents into their respective asset category. These reclassifications are not material as the changes do not impact the 2012 financial statements nor the total plan assets previously reported, rather just the presentation of the components of total plan assets in the table above.