Investments - Loans by Loan to Value (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Mar. 31, 2025	Sep. 30, 2025	Dec. 31, 2024
Schedule of Loans by Loan to Value Ratio [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		$ 486	$ 229
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		272	256
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		210	535
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		552	430
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		429	212
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		2,480	1,970
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss		4,429	3,632
One America
Schedule of Loans by Loan to Value Ratio [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss		$ 800
0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Loans Receivable, Loan to Value Ratio, Minimum	0.00%	0.00%
Loans Receivable, Loan to Value Ratio, Maximum	50.00%	50.00%
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		$ 193	111
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		135	76
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		73	201
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		226	189
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		199	149
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		2,323	1,827
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss		$ 3,149	2,553
50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Loans Receivable, Loan to Value Ratio, Minimum	50.00%	50.00%
Loans Receivable, Loan to Value Ratio, Maximum	60.00%	60.00%
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		$ 251	107
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		126	151
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		137	240
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		243	148
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		171	63
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		155	126
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss		$ 1,083	835
60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Loans Receivable, Loan to Value Ratio, Minimum	60.00%	60.00%
Loans Receivable, Loan to Value Ratio, Maximum	70.00%	70.00%
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		$ 42	11
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		11	29
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		0	94
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		83	93
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		59	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		0	1
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss		$ 195	228
70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Loans Receivable, Loan to Value Ratio, Minimum	70.00%	70.00%
Loans Receivable, Loan to Value Ratio, Maximum	80.00%	80.00%
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		$ 0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year			0
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss		$ 0	0
Debt-to-Value Ratio, 80 to 100 Percent
Schedule of Loans by Loan to Value Ratio [Line Items]
Loans Receivable, Loan to Value Ratio, Minimum	80.00%	80.00%
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		$ 0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		2	16
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss		$ 2	$ 16