Fair Value - Separate Accounts Fair Value (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	$ 3,187	$ 3,250
Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	3,138	3,204
Recurring | Other Receivables
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	49	46
Recurring | Cash and cash equivalents
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	162	168
Recurring | Debt securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	2,405	2,507
Recurring | Common/collective trusts
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	571	529
Recurring | Level 1
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	589	560
Recurring | Level 1 | Cash and cash equivalents
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	0	2
Recurring | Level 1 | Debt securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	589	558
Recurring | Level 1 | Common/collective trusts
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	0	0
Recurring | Level 2
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	2,549	2,644
Recurring | Level 2 | Cash and cash equivalents
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	162	166
Recurring | Level 2 | Debt securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	1,816	1,949
Recurring | Level 2 | Common/collective trusts
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	571	529
Recurring | Level 3
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	0	0
Recurring | Level 3 | Cash and cash equivalents
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	0	0
Recurring | Level 3 | Debt securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	0	0
Recurring | Level 3 | Common/collective trusts
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	$ 0	$ 0