Investments - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Investment [Line Items]
Held-to-maturity investments	$ 108	$ 79
Foreign government debt, within one year	96
Foreign government debt, after ten years	12
Total trading investments	785	536
Consolidated Sponsored Investment Funds [Member]
Investment [Line Items]
Total trading investments	700	443
Deferred Compensation Plan Fund [Member]
Investment [Line Items]
Total trading investments	65	64
Equity and Debt Securities Held in Separate Investment Accounts [Member]
Investment [Line Items]
Total trading investments	20	29
Consolidated Voting Rights Entities [Member] \| Consolidated Sponsored Investment Funds [Member]
Investment [Line Items]
Trading securities, debt	437	223
Trading securities, equity	$ 263	$ 220
Minimum [Member]
Investment [Line Items]
Maturity period of investments	5 years
Maximum [Member]
Investment [Line Items]
Maturity period of investments	10 years

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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.

+ References

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-Publisher SEC
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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 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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Fair value of held-to-maturity debt securities maturing in the next 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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Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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