Income Taxes - Schedule of Expiration Periods of Deferred Tax Assets (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	$ 2,229
Tax credit carryforwards	567
Other	3,592
Valuation allowance	(1,804)
Deferred tax assets, net	4,584	5,002
Expires Within 10 Years [Member]
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	377
Tax credit carryforwards	417
Other
Valuation allowance	(412)
Deferred tax assets, net	382
Expires Within 11-20 Years [Member]
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	898
Tax credit carryforwards	75
Other
Valuation allowance	(843)
Deferred tax assets, net	130
No Expiration [Member]
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	954
Tax credit carryforwards	75
Other	498
Valuation allowance	(268)
Deferred tax assets, net	1,259
Other [Member]
Tax Credit Carryforward [Line Items]
Tax loss carryforwards
Tax credit carryforwards
Other	3,094
Valuation allowance	(281)
Deferred tax assets, net	$ 2,813