Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax And Carryforwards [Line Items]
Capital loss carryover	$ 15	$ 134
Undistributed Earnings of Foreign Subsidiaries	46
Deferred Tax Assets, Investments	11
Interest and penalties accrued for unrecognized tax benefits, current period	0	62	$ 10
Interest and penalties accrued for unrecognized tax benefits, total	0	1	63
Unrecognized tax benefits that would impact the effective tax rate	1	48	$ 91
General Business Tax Credit Carryforward [Member]
Income Tax And Carryforwards [Line Items]
Operating loss carryforward, amount to expire	14
Federal [Member]
Income Tax And Carryforwards [Line Items]
Operating loss carryforward	134	4,200
Capital loss carryover	42
Foreign Tax Authority [Member]
Income Tax And Carryforwards [Line Items]
Operating loss carryforward	6	110
Tax Credit Carryforward, Amount	19	14
State [Member]
Income Tax And Carryforwards [Line Items]
Operating loss carryforward	$ 85	8,200
Adjustments for New Accounting Principle, Early Adoption [Member] | Other Noncurrent Liabilities [Member]
Income Tax And Carryforwards [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ 212