Separate accounts (Fair value of assets) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Separate Account Investment [Line Items]
Separate account assets	$ 6,231	$ 5,573
Separate Account, Cash and Cash Equivalents
Fair Value, Separate Account Investment [Line Items]
Separate account assets	234	65
Mutual funds
Fair Value, Separate Account Investment [Line Items]
Separate account assets	5,931	5,417
Fixed maturities
Fair Value, Separate Account Investment [Line Items]
Separate account assets	$ 66	$ 91