Revenue - Summary of Investment Advisory, Administration Fees and Securities Lending Revenue by Client Type, Investment Style and Product Type (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	$ 2,947	$ 2,523
Cash Management [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	151	127
Equity [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,540	1,281
Equity [Member] \| Active [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	438	400
Equity [Member] \| iShares ETFs [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	926	721
Fixed Income [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	757	677
Fixed Income [Member] \| Active [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	456	407
Fixed Income [Member] \| iShares ETFs [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	208	185
Multi-asset [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	296	272
Alternatives [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	203	166
Long-term [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,796	2,396
Revenue by Client Type [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,947	2,523
Revenue by Client Type [Member] \| Retail
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	855	776
Revenue by Client Type [Member] \| iShares ETFs [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,158	925
Revenue by Client Type [Member] \| Institutional [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	783	695
Revenue by Client Type [Member] \| Institutional [Member] \| Active [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	527	458
Revenue by Client Type [Member] \| Institutional [Member] \| Index [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	256	237
Revenue by Client Type [Member] \| Cash Management [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	151	127
Revenue by Client Type [Member] \| Long-term [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,796	2,396
Revenue by Investment Style [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,947	2,523
Revenue by Investment Style [Member] \| Active [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,365	1,220
Revenue by Investment Style [Member] \| Index and iShares ETFs [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,431	1,176
Revenue by Investment Style [Member] \| Cash Management [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	151	127
Revenue by Investment Style [Member] \| Long-term [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,796	2,396
Revenue by Product Type [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,947	2,523
Revenue by Product Type [Member] \| Cash Management [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	151	127
Revenue by Product Type [Member] \| Equity [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,540	1,281
Revenue by Product Type [Member] \| Fixed Income [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	757	677
Revenue by Product Type [Member] \| Multi-asset [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	296	272
Revenue by Product Type [Member] \| Alternatives [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	203	166
Revenue by Product Type [Member] \| Long-term [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	$ 2,796	$ 2,396

Revenue - Summary of Investment Advisory, Administration Fees and Securities Lending Revenue by Client Type, Investment Style and Product Type (Detail) - USD ($)
$ in Millions