Income Taxes - Schedule of Expiration Periods of Deferred Tax Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	$ 1,917
Tax credit carryforwards	693
Other	3,914
Valuation allowance	(2,037)
Deferred tax assets, net	4,487	$ 4,589
Expires Within 10 Years [Member]
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	361
Tax credit carryforwards	492
Valuation allowance	(596)
Deferred tax assets, net	257
Expires Within 11-20 Years [Member]
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	694
Tax credit carryforwards	103
Valuation allowance	(704)
Deferred tax assets, net	93
No Expiration [Member]
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	862
Tax credit carryforwards	98
Other	473
Valuation allowance	(423)
Deferred tax assets, net	1,010
Other [Member]
Tax Credit Carryforward [Line Items]
Other	3,441
Valuation allowance	(314)
Deferred tax assets, net	$ 3,127