Investments (Net Unrealized Gains Losses on Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Gain (Loss) on Securities [Line Items]
Net unrealized gains (losses) on investments	$ (17,251)	$ (25,004)	$ 40,438
Fixed maturities | Available-for-sale | With an allowance
Gain (Loss) on Securities [Line Items]
Net unrealized gains (losses) on investments	(72)	(45)	23
Fixed maturities | Available-for-sale | Without an allowance
Gain (Loss) on Securities [Line Items]
Net unrealized gains (losses) on investments	(18,045)	(27,545)	39,467
Derivatives designated as cash flow hedges
Gain (Loss) on Securities [Line Items]
Net unrealized gains (losses) on investments	869	2,616	1,019
Derivatives designated as fair value hedges
Gain (Loss) on Securities [Line Items]
Net unrealized gains (losses) on investments	(60)	(54)	(35)
Other investments
Gain (Loss) on Securities [Line Items]
Net unrealized gains (losses) on investments	57	$ 24	$ (36)
Without an allowance | Available-for-sale
Gain (Loss) on Securities [Line Items]
Net unrealized gains (losses) on investments	$ 126