v3.7.0.1
Fair Value Disclosures - Additional Information (Detail) - USD ($)
$ in Millions
Jun. 30, 2017
Dec. 31, 2016
Significant Unobservable Inputs (Level 3) [Member] | Private/ Public Equity [Member] | Consolidated Variable Interest Entities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments $ 113 $ 112