Variable Interest Entities - Narrative (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Assets	$ 155,036,700,000	$ 183,889,800,000	$ 170,003,900,000
Liabilities	143,777,200,000	171,873,000,000
Investment company, voluntary fee waived	64,200,000	287,800,000
Fair value, investments, entities that calculate net asset value per share, seed capital investments	19,900,000	0
Unfunded commitments		0
Tax Credit Structures
Variable Interest Entity [Line Items]
Exposure to loss from liquidity arrangements and obligations to purchase assets	0
Affordable housing tax credits and other tax benefits	99,100,000	87,200,000
Other Assets
Variable Interest Entity [Line Items]
Investments in community development projects, carrying amount, assets	904,300,000	916,800,000
Other Assets | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	867,200,000	880,000,000
Other Liabilities
Variable Interest Entity [Line Items]
Investments in community development projects, carrying amount, liabilities	218,900,000	289,300,000
Other Liabilities | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Liabilities	$ 210,100,000	$ 280,500,000