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Income Taxes - Additional information (Detail) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Income Taxes [Line Items]    
Effective tax rate of income (loss) before income taxes 31.70% 35.40%
Reduction in income tax expense $ 32  
Equity in net losses of unconsolidated entities 32 $ 7
Interest expense 92 95
Investments Qualifying for Federal Tax Credits [Member]    
Income Taxes [Line Items]    
Equity in net losses of unconsolidated entities 6 6
Interest expense 1 1
Income tax benefit, including tax credits, from equity method investment $ 11 $ 11