Derivative Instruments - Schedule of Pre-Tax Income (Loss) Effects of Cash Flow Hedges (Details) - Cash flow hedges - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	$ 16	$ (158)	$ 45	$ (63)
Gain (loss) reclassified into net income (loss) from OCI	48	47	94	96
Gain (loss) recognized in net income (loss)	0	0	0	0
Interest rate swaps hedging assets \| Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	0	0	0	0
Gain (loss) reclassified into net income (loss) from OCI	5	1	8	2
Gain (loss) recognized in net income (loss)	0	0	0	0
Interest rate swaps hedging assets \| Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	0	(85)	35	(23)
Gain (loss) reclassified into net income (loss) from OCI	42	47	86	95
Interest rate swaps hedging liabilities \| Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in net income (loss)	0	0	0	0
Interest rate swaps hedging liabilities \| Location, Statement of Income, Balance [Axis]: us-gaap:InterestExpense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	3	(1)	2	(3)
Gain (loss) reclassified into net income (loss) from OCI	0	(1)	(1)	(1)
Foreign currency swaps \| Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in net income (loss)	0	0	0	0
Foreign currency swaps \| Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	(3)	(13)	2	(14)
Gain (loss) reclassified into net income (loss) from OCI	0	0	0	0
Forward bond purchase commitments \| Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) recognized in OCI	16	(59)	6	(23)
Gain (loss) reclassified into net income (loss) from OCI	1	0	1	0
Gain (loss) recognized in net income (loss)	$ 0	$ 0	$ 0	$ 0