Investments - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2017	Dec. 31, 2016
Investment [Line Items]
Held-to-maturity investments	$ 74	$ 51
Foreign government debt, after five years through ten years	11
Held-to-maturity investments, after ten years	63
Total trading investments	$ 719	$ 625
PennyMac [Member]
Investment [Line Items]
Ownership percentage	20.00%	20.00%
Shares and units	16	16
Carrying value - equity method investment	$ 317	$ 301
Fair value of equity method investments	260	259
Consolidated Sponsored Investment Funds [Member]
Investment [Line Items]
Total trading investments	503	465
Deferred Compensation Plan Fund [Member]
Investment [Line Items]
Total trading investments	52	59
Equity and Debt Securities Held in Separate Investment Accounts [Member]
Investment [Line Items]
Total trading investments	164	101
Consolidated Entities [Member] \| Consolidated Sponsored Investment Funds [Member]
Investment [Line Items]
Trading securities, debt	242	246
Trading securities, equity	$ 261	$ 219

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Line items represent reporting concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Fair value portion of investments accounted under the equity method.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Fair value of held-to-maturity debt securities maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of held-to-maturity debt securities maturing after the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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