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Segment Information - Schedule of Segment Reporting Information, by Segment (Parenthetical) (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Segment Reporting Information [Line Items]      
Interest expense $ 566 $ 570 $ 346
Operating Segments      
Segment Reporting Information [Line Items]      
Interest income 21 26 22
Interest expense $ 53 $ 53 $ 30