v3.26.3
INVESTMENTS - Securities Lending Transactions Accounted for as Secured Borrowings (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings $ 6,874 $ 3,989
Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 6,634 3,989
Japan government and agencies | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 5,389 2,920
Public utilities | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 50 54
Banks/financial institutions | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 203 150
Other corporate | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 992 865
Maturity Overnight and Continuous | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings [1] 1,245 1,069
Maturity Overnight and Continuous | Japan government and agencies | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings [1] 0 0
Maturity Overnight and Continuous | Public utilities | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings [1] 50 54
Maturity Overnight and Continuous | Banks/financial institutions | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings [1] 203 150
Maturity Overnight and Continuous | Other corporate | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings [1] 992 865
Maturity up to 30 Days | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 2,454 1,591
Maturity up to 30 Days | Japan government and agencies | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 2,454 1,591
Maturity up to 30 Days | Public utilities | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 0 0
Maturity up to 30 Days | Banks/financial institutions | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 0 0
Maturity up to 30 Days | Other corporate | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 0 0
Maturity 30 to 90 Days | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 2,935 1,329
Maturity 30 to 90 Days | Japan government and agencies | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 2,935 1,329
Maturity 30 to 90 Days | Public utilities | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 0 0
Maturity 30 to 90 Days | Banks/financial institutions | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings 0 0
Maturity 30 to 90 Days | Other corporate | Securities lending transactions    
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]    
Total borrowings $ 0 $ 0
[1] The related loaned security, under the Company's U.S. securities lending program, can be returned to the Company at the transferee's discretion; therefore, they are classified as Overnight and Continuous.