Investments - Fixed Maturity Securities in Continuous Loss Position (Details)	Sep. 30, 2026 security	Sep. 30, 2026 position	Dec. 31, 2025 security	Dec. 31, 2025 position
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months	1,540	1,540	1,649	1,649
Investment Grade
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months		1,492		1,592
Non Investment Grade
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months		33		34
AAA
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months		131		140
AA
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months		809		860
A
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months		262		275
BBB
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months		290		317
BB
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months		19		24
B
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months		10		8
CCC or lower
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months		4		2
Not rated
Debt Securities, Available-for-Sale [Line Items]
Number of position with a gross unrealized loss, more than 12 months		15		23