Policyholder Account Balances - Summary of Range Guaranteed Minimum Crediting Rate (Parenthetical) (Detail) $ in Millions	Sep. 30, 2024 USD ($) bps		Dec. 31, 2023 USD ($) bps
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 14,864		$ 15,540
1–50 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	824		893
51–150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 1,202		$ 1,204
Greater than than 150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate | bps	150		150
Policyholder account balances	$ 56		$ 31
Minimum | 1–50 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate | bps	1		1
Minimum | 51–150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate | bps	51		51
Maximum | 1–50 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate | bps	50		50
Maximum | 51–150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate | bps	150		150
Less than 2.00%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 213	[1]	$ 257	[2]
Less than 2.00% | 1–50 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	52		97
Less than 2.00% | 51–150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	59		39
Less than 2.00% | Greater than than 150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 0		$ 0
Less than 2.00% | Minimum
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	2.00%		2.00%
2.00%–2.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 863	[1]	$ 1,282	[2]
2.00%–2.99% | 1–50 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	99		81
2.00%–2.99% | 51–150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	0		0
2.00%–2.99% | Greater than than 150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 0		$ 0
2.00%–2.99% | Minimum
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	2.00%		2.00%
2.00%–2.99% | Maximum
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	2.99%		2.99%
3.00%–3.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 3,681	[1]	$ 3,617	[2]
3.00%–3.99% | 1–50 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	655		699
3.00%–3.99% | 51–150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	1,125		1,155
3.00%–3.99% | Greater than than 150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 56		$ 31
3.00%–3.99% | Minimum
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	3.00%		3.00%
3.00%–3.99% | Maximum
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	3.99%		3.99%
4.00% and greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 2,385	[1]	$ 2,505	[2]
4.00% and greater | 1–50 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	18		16
4.00% and greater | 51–150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	18		10
4.00% and greater | Greater than than 150 basis points above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 0		$ 0
4.00% and greater | Minimum
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	4.00%		4.00%
Universal Life Insurance and Investment Contracts
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balances	$ 4,573		$ 4,807

[1] Excludes universal life insurance and investment contracts of $4,573 million that have a market component to their crediting strategy.

[2] Excludes universal life insurance and investment contracts of $4,807 million that have a market component to their crediting strategy.