Investments - Commercial Mortgage Loans (Details) - Real Estate Loan - Commercial Portfolio Segment $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Schedule of Investments [Line Items]
Carrying value, after allowance for credit loss, including assets held for sale	$ 1,460	$ 1,533
Weighted Average
Schedule of Investments [Line Items]
Average Debt Service Coverage Ratio, including assets held for sale	1.81	1.82
Average Loan-to-Value Ratio, including assets held for sale	0.67	0.64
Below 60%
Schedule of Investments [Line Items]
Carrying value, after allowance for credit loss, including assets held for sale	$ 645	$ 802
Below 60% | Weighted Average
Schedule of Investments [Line Items]
Average Debt Service Coverage Ratio, including assets held for sale	2.15	2.13
60% to 79%
Schedule of Investments [Line Items]
Carrying value, after allowance for credit loss, including assets held for sale	$ 574	$ 574
60% to 79% | Weighted Average
Schedule of Investments [Line Items]
Average Debt Service Coverage Ratio, including assets held for sale	1.85	1.77
80% to 100%
Schedule of Investments [Line Items]
Carrying value, after allowance for credit loss, including assets held for sale	$ 241	$ 157
80% to 100% | Weighted Average
Schedule of Investments [Line Items]
Average Debt Service Coverage Ratio, including assets held for sale	0.92	0.65