Activity Associated with Derivative Instruments (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($) Policies
Derivative [Line Items]
Notional amount, beginning balance	$ 12,634
Additions	4,443
Maturities/ terminations	(3,211)
Notional amount, ending balance	13,866
Designated As Hedging Instrument
Derivative [Line Items]
Notional amount, beginning balance	10,181
Additions	1,772
Maturities/ terminations	(399)
Notional amount, ending balance	11,554
Designated As Hedging Instrument | Cash Flow Hedges
Derivative [Line Items]
Notional amount, beginning balance	10,181
Additions	1,772
Maturities/ terminations	(399)
Notional amount, ending balance	11,554
Designated As Hedging Instrument | Cash Flow Hedges | Interest rate swaps
Derivative [Line Items]
Notional amount, beginning balance	8,975
Additions	231
Maturities/ terminations	(399)
Notional amount, ending balance	8,807
Designated As Hedging Instrument | Cash Flow Hedges | Foreign currency swaps
Derivative [Line Items]
Notional amount, beginning balance	131
Additions	13
Maturities/ terminations	0
Notional amount, ending balance	144
Designated As Hedging Instrument | Forward bond purchase commitments | Cash Flow Hedges
Derivative [Line Items]
Notional amount, beginning balance	1,075
Additions	1,528
Maturities/ terminations	0
Notional amount, ending balance	2,603
Derivatives not designated as hedges
Derivative [Line Items]
Notional amount, beginning balance	2,453
Additions	2,671
Maturities/ terminations	(2,812)
Notional amount, ending balance	2,312
Derivatives not designated as hedges | Equity index options
Derivative [Line Items]
Notional amount, beginning balance	702
Additions	308
Maturities/ terminations	(357)
Notional amount, ending balance	653
Derivatives not designated as hedges | Financial futures
Derivative [Line Items]
Notional amount, beginning balance	1,251
Additions	2,363
Maturities/ terminations	(2,455)
Notional amount, ending balance	$ 1,159
Derivatives not designated as hedges | Fixed indexed annuity embedded derivatives
Derivative [Line Items]
Notional amount, beginning balance | Policies	5,826
Additions | Policies	0
Maturities/ terminations | Policies	(530)
Notional amount, ending balance | Policies	5,296
Derivatives not designated as hedges | Indexed universal life embedded derivatives
Derivative [Line Items]
Notional amount, beginning balance | Policies	749
Additions | Policies	0
Maturities/ terminations | Policies	(17)
Notional amount, ending balance | Policies	732
Derivatives not designated as hedges | Forward bond purchase commitments
Derivative [Line Items]
Notional amount, beginning balance	$ 500
Additions	0
Maturities/ terminations	0
Notional amount, ending balance	$ 500