Fair Value - Carrying and Fair Value By Level of Financial Instruments Not Recorded at Fair Value on Consolidated Balance Sheet (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Assets:
Other invested assets	$ 10,839	$ 9,749
Liabilities:
Short-term borrowings	150	365
Options	$ 28	150
Derivative Liability, Statement Of Financial Position Extensible Enumeration Not Disclosed Flag	false
Reported Value Measurement
Assets:
Other invested assets	$ 781	642
Liabilities:
Short-term borrowings	150	365
Notes	31,896	30,867
Options	1,726	1,415
Estimate of Fair Value Measurement
Assets:
Other invested assets	762	610
Liabilities:
Short-term borrowings	150	365
Notes	30,207	28,460
Options	3,044	1,873
Level I
Liabilities:
Options	0	0
Level I | Estimate of Fair Value Measurement
Assets:
Other invested assets	0	0
Liabilities:
Short-term borrowings	0	0
Notes	0	0
Options	0	0
Level II
Liabilities:
Options	28	150
Level II | Estimate of Fair Value Measurement
Assets:
Other invested assets	0	0
Liabilities:
Short-term borrowings	150	365
Notes	30,207	28,460
Options	0	0
Level III
Liabilities:
Options	0	0
Level III | Estimate of Fair Value Measurement
Assets:
Other invested assets	762	610
Liabilities:
Short-term borrowings	0	0
Notes	0	0
Options	$ 3,044	$ 1,873