XML 81 R59.htm IDEA: XBRL DOCUMENT v3.22.4
Debt Securities (Investments in Debt Securities, Classified as Available-For-Sale) (Detail) - USD ($)
$ in Millions
Dec. 31, 2022
Dec. 31, 2021
Schedule Of Available For Sale Securities [Line Items]    
Debt Securities, Amortized cost $ 9,170 $ 9,317
Debt Securities, Gross unrealized gains 9 127
Debt Securities, Gross unrealized losses (1,009) (82)
Debt securities, Estimated fair value 8,170 9,362
U.S. Treasury bonds    
Schedule Of Available For Sale Securities [Line Items]    
Debt Securities, Amortized cost 309 123
Debt Securities, Gross unrealized gains 1 1
Debt Securities, Gross unrealized losses (7) (1)
Debt securities, Estimated fair value 303 123
Municipal bonds    
Schedule Of Available For Sale Securities [Line Items]    
Debt Securities, Amortized cost 1,671 1,607
Debt Securities, Gross unrealized gains 3 59
Debt Securities, Gross unrealized losses (195) (17)
Debt securities, Estimated fair value 1,479 1,649
Foreign government bonds    
Schedule Of Available For Sale Securities [Line Items]    
Debt Securities, Amortized cost 208 228
Debt Securities, Gross unrealized gains 0 2
Debt Securities, Gross unrealized losses (14) (3)
Debt securities, Estimated fair value 194 227
Governmental agency bonds    
Schedule Of Available For Sale Securities [Line Items]    
Debt Securities, Amortized cost 248 175
Debt Securities, Gross unrealized gains 0 3
Debt Securities, Gross unrealized losses (19) (1)
Debt securities, Estimated fair value 229 177
Governmental agency mortgage-backed securities    
Schedule Of Available For Sale Securities [Line Items]    
Debt Securities, Amortized cost 5,253 5,620
Debt Securities, Gross unrealized gains 1 34
Debt Securities, Gross unrealized losses (653) (47)
Debt securities, Estimated fair value 4,601 5,607
U.S. corporate debt securities    
Schedule Of Available For Sale Securities [Line Items]    
Debt Securities, Amortized cost 1,004 1,071
Debt Securities, Gross unrealized gains 2 19
Debt Securities, Gross unrealized losses (85) (9)
Debt securities, Estimated fair value 921 1,081
Foreign corporate debt securities    
Schedule Of Available For Sale Securities [Line Items]    
Debt Securities, Amortized cost 477 493
Debt Securities, Gross unrealized gains 2 9
Debt Securities, Gross unrealized losses (36) (4)
Debt securities, Estimated fair value $ 443 $ 498