Reinsurance - Effect of Reinsurance on Benefit Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Reinsurance Disclosures [Abstract]
Direct	$ 143,820	$ 123,602	$ 119,409
Assumed	4,475	4,021	4,984
Ceded	(72)	(56)	(63)
Net benefit expense	$ 148,223	$ 127,567	$ 124,330