Separate Accounts (Separate Account Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Separate Account Investment [Line Items]
Separate account assets	$ 118,143,256	$ 119,188,485
U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value, Separate Account Investment [Line Items]
Separate account assets	15,548	2,954
Obligations of U.S. states and their political subdivisions authorities
Fair Value, Separate Account Investment [Line Items]
Separate account assets	115	0
U.S. corporate securities
Fair Value, Separate Account Investment [Line Items]
Separate account assets	24,458	9,504
Foreign corporate securities
Fair Value, Separate Account Investment [Line Items]
Separate account assets	3,158	1,763
Asset-Backed Securities
Fair Value, Separate Account Investment [Line Items]
Separate account assets	1,099	0
Mortgage-backed securities
Fair Value, Separate Account Investment [Line Items]
Separate account assets	82	186
Equity
Fair Value, Separate Account Investment [Line Items]
Separate account assets	73,226,610	72,614,821
Fixed Income
Fair Value, Separate Account Investment [Line Items]
Separate account assets	33,828,097	37,065,162
Other
Fair Value, Separate Account Investment [Line Items]
Separate account assets	4,431,975	4,101,661
Equity securities
Fair Value, Separate Account Investment [Line Items]
Separate account assets	126,792	104,159
Other invested assets
Fair Value, Separate Account Investment [Line Items]
Separate account assets	6,444,077	5,258,900
Short-term investments
Fair Value, Separate Account Investment [Line Items]
Separate account assets	2,559	2,126
Cash and cash equivalents
Fair Value, Separate Account Investment [Line Items]
Separate account assets	$ 38,686	$ 27,249