Commitments and Contingencies - Additional Information (Detail) $ in Millions	6 Months Ended
Jun. 30, 2019 USD ($) ft²	Dec. 31, 2018 USD ($)
Commitment And Contingencies [Line Items]
Various capital commitments to fund sponsored investment funds, including funds of private equity funds, real assets funds, opportunistic funds and distressed credit funds	$ 605
Total operating lease minimum commitments		$ 2,157
Derivative maximum risk of loss for credit protection	17	$ 17
Securities lending loan balances indemnified	205,000
Collateral for indemnified securities	219,000
Other Liabilities [Member]
Commitment And Contingencies [Line Items]
Contingent consideration at fair value	$ 168
Operating Lease [Member]
Commitment And Contingencies [Line Items]
Area of office space \| ft²	847,000
Operating leases, term of contract	20 years
Expected lease commencement date	2023-05
Annual base rental payments first five years	$ 51
Annual base rental payments five to ten years	58
Annual base rental payments ten to fifteen years	66
Annual base rental payments fifteen to twenty years	74
Total operating lease minimum commitments	$ 1,200

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