Consolidated Balance Sheets (Parentheticals) (Unaudited) $ in Millions	Mar. 31, 2026 USD ($) shares	Dec. 31, 2025 USD ($) shares
Statement of Financial Position [Abstract]
Short-term investments, amortized cost	$ 5,067	$ 4,840
Fixed maturities available-for-sale, valuation allowance	50	52
Fixed maturities available-for-sale, amortized cost	127,301	124,726
Private debt held-to-maturity, valuation allowance	2	3
Restricted cash	203	198
Insurance and reinsurance balances receivable, valuation allowance	63	62
Valuation allowance for uncollectible reinsurance	$ 320	$ 320
Common Shares, shares issued | shares	400,120,847	412,107,421
Common Stock, Shares Authorized | shares	400,120,847	412,107,421
Common Shares, shares outstanding | shares	388,495,580	391,101,227
Treasury Stock, Common, Shares | shares	11,625,267	21,006,194
Short-term investments	$ 5,067	$ 4,840
Equity securities	10,916	10,801
Private equities	17,132	17,239
Other investments	11,170	10,749
Cash, including restricted cash	2,634	2,470
Other assets	9,341	9,222
Repurchase agreements	3,736	3,324
Noncontrolling interests	6,124	6,022
Variable Interest Entity, Primary Beneficiary
Short-term investments	109	105
Equity securities	2,379	2,275
Private equities	23	22
Other investments	5,828	5,818
Cash, including restricted cash	258	168
Other assets	82	58
Repurchase agreements	983	956
Other liabilities	64	159
Noncontrolling interests	$ 5,316	$ 5,133