Summary of carrying value of limited partnerships and commitments to fund (Detail) - USD ($) $ in Millions		Jun. 30, 2022	Dec. 31, 2021
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Limited partnerships, carrying value		$ 2,123	$ 1,900
Off-balance sheet risk		1,409	1,185
Limited Partnerships
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Limited partnerships, carrying value		1,649	1,462
Assets Measured Using Net Asset Value | Limited Partnerships Private Equity Funds
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Limited partnerships, carrying value	[1]	1,483	1,312
Off-balance sheet risk	[1]	1,080	950
Assets Measured Using Net Asset Value | Limited Partnerships Real Estate Funds
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Limited partnerships, carrying value	[2]	84	67
Off-balance sheet risk	[2]	145	101
Assets Measured Using Net Asset Value | Limited Partnerships Infrastructure Funds
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Limited partnerships, carrying value	[3]	59	57
Off-balance sheet risk	[3]	11	13
Assets Measured Using Net Asset Value | Limited Partnerships
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Limited partnerships, carrying value		1,626	1,436
Off-balance sheet risk		1,236	1,064
Accounted For Under Equity method of Accounting | Limited Partnerships
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Limited partnerships, carrying value		473	437
Off-balance sheet risk		172	120
Low-Income Housing Tax Credits | Limited Partnerships
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Limited partnerships, carrying value	[4]	1	1
Off-balance sheet risk	[4]	0	0
Accounted for at Fair Value | Limited Partnerships
Schedule of Carrying Value of Limited Partnerships and Commitments To Fund [Line Items]
Limited partnerships, carrying value		23	26
Off-balance sheet risk		$ 1	$ 1

[1] This class employs various investment strategies such as leveraged buyout, growth equity, venture capital and mezzanine financing, generally investing in debt or equity positions directly in companies or assets of various sizes across diverse industries globally, primarily concentrated in North America.

[2] This class invests in real estate in North America, Europe and Asia via direct property ownership, joint ventures, mortgages and investments in debt and equity instruments.

[3] This class invests in the debt or equity of cash flow generating assets diversified across a variety of industries, including transportation, energy infrastructure, renewable power, social infrastructure, power generation, water, telecommunications and other regulated entities globally.

[4] Relates to limited partnership investments that invest in affordable housing projects that qualify for the Low-Income Housing Tax Credit and are accounted for using the proportional amortization method.