Investments - Fixed Maturity Securities in Continuous Loss Position (Details)	Sep. 30, 2025 security	Sep. 30, 2025 position	Dec. 31, 2024 security	Dec. 31, 2024 position
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months	1,708	1,708	1,862	1,862
Investment Grade
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months		1,625		1,744
Non Investment Grade
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months		39		62
AAA
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months		140		155
AA
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months		882		899
A
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months		286		320
BBB
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months		317		370
BB
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months		29		40
B
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months		8		18
CCC or lower
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months		2		4
Not rated
Gain (Loss) on Securities [Line Items]
Number of position with a gross unrealized loss, more than 12 months		44		56