Fair Value - Composition of Investment Portfolio by Major Security Type (Detail) - USD ($)
$ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
Jun. 30, 2025 |
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
$ 92,413
|
$ 92,871
|
$ 84,375
|
| Equity securities |
4,808
|
4,502
|
4,235
|
| Investments, fair value |
97,221
|
97,373
|
88,610
|
| Fair value |
7,758
|
6,345
|
6,294
|
| Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
276
|
404
|
500
|
| Common equities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
4,532
|
4,098
|
3,735
|
| Common equities | Common Stocks, excluding Other Risk |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
4,493
|
4,062
|
3,703
|
| Common equities | Other risk investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
39
|
36
|
32
|
| Total fixed maturities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
90,435
|
82,866
|
82,272
|
| Total fixed maturities | U.S. government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
43,781
|
43,298
|
46,810
|
| Total fixed maturities | State and local government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
3,852
|
3,303
|
2,964
|
| Total fixed maturities | Foreign government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
16
|
17
|
17
|
| Total fixed maturities | Corporate and other debt |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
21,591
|
19,991
|
18,122
|
| Total fixed maturities | Residential mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
4,282
|
3,175
|
2,660
|
| Total fixed maturities | Commercial mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
7,453
|
5,973
|
5,049
|
| Total fixed maturities | Other asset-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
9,460
|
7,109
|
6,650
|
| Total fixed maturities | Debt Securities | U.S. government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
43,781
|
43,298
|
46,810
|
| Total fixed maturities | Debt Securities | State and local government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
3,852
|
3,303
|
2,964
|
| Total fixed maturities | Debt Securities | Foreign government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
16
|
17
|
17
|
| Total fixed maturities | Debt Securities | Corporate and other debt |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
21,591
|
19,991
|
18,122
|
| Total fixed maturities | Asset-backed Securities | Residential mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
4,282
|
3,175
|
2,660
|
| Total fixed maturities | Asset-backed Securities | Commercial mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
7,453
|
5,973
|
5,049
|
| Total fixed maturities | Asset-backed Securities | Other asset-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
9,460
|
7,109
|
6,650
|
| Short-term investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
1,978
|
10,005
|
2,103
|
| Fair Value, Inputs, Level 1 |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
45,711
|
53,108
|
48,732
|
| Equity securities |
4,485
|
4,057
|
3,694
|
| Investments, fair value |
50,196
|
57,165
|
52,426
|
| Fair value |
0
|
0
|
0
|
| Fair Value, Inputs, Level 1 | Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 1 | Common equities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
4,485
|
4,057
|
3,694
|
| Fair Value, Inputs, Level 1 | Common equities | Common Stocks, excluding Other Risk |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
4,485
|
4,057
|
3,694
|
| Fair Value, Inputs, Level 1 | Common equities | Other risk investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 1 | Total fixed maturities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
43,781
|
43,298
|
46,810
|
| Fair Value, Inputs, Level 1 | Total fixed maturities | Debt Securities | U.S. government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
43,781
|
43,298
|
46,810
|
| Fair Value, Inputs, Level 1 | Total fixed maturities | Debt Securities | State and local government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 1 | Total fixed maturities | Debt Securities | Foreign government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 1 | Total fixed maturities | Debt Securities | Corporate and other debt |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 1 | Total fixed maturities | Asset-backed Securities | Residential mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 1 | Total fixed maturities | Asset-backed Securities | Commercial mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 1 | Total fixed maturities | Asset-backed Securities | Other asset-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 1 | Short-term investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
1,930
|
9,810
|
1,922
|
| Fair Value, Inputs, Level 2 |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
46,548
|
39,759
|
35,638
|
| Equity securities |
227
|
344
|
440
|
| Investments, fair value |
46,775
|
40,103
|
36,078
|
| Fair value |
7,758
|
6,345
|
6,294
|
| Fair Value, Inputs, Level 2 | Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
227
|
344
|
440
|
| Fair Value, Inputs, Level 2 | Common equities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 2 | Common equities | Common Stocks, excluding Other Risk |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 2 | Common equities | Other risk investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 2 | Total fixed maturities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
46,500
|
39,564
|
35,457
|
| Fair Value, Inputs, Level 2 | Total fixed maturities | Debt Securities | U.S. government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 2 | Total fixed maturities | Debt Securities | State and local government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
3,852
|
3,303
|
2,964
|
| Fair Value, Inputs, Level 2 | Total fixed maturities | Debt Securities | Foreign government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
16
|
17
|
17
|
| Fair Value, Inputs, Level 2 | Total fixed maturities | Debt Securities | Corporate and other debt |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
21,587
|
19,987
|
18,117
|
| Fair Value, Inputs, Level 2 | Total fixed maturities | Asset-backed Securities | Residential mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
4,282
|
3,175
|
2,660
|
| Fair Value, Inputs, Level 2 | Total fixed maturities | Asset-backed Securities | Commercial mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
7,453
|
5,973
|
5,049
|
| Fair Value, Inputs, Level 2 | Total fixed maturities | Asset-backed Securities | Other asset-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
9,310
|
7,109
|
6,650
|
| Fair Value, Inputs, Level 2 | Short-term investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
48
|
195
|
181
|
| Fair Value, Inputs, Level 3 |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
154
|
4
|
5
|
| Equity securities |
96
|
101
|
101
|
| Investments, fair value |
250
|
105
|
106
|
| Fair value |
0
|
0
|
0
|
| Fair Value, Inputs, Level 3 | Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
49
|
60
|
60
|
| Fair Value, Inputs, Level 3 | Common equities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
47
|
41
|
41
|
| Fair Value, Inputs, Level 3 | Common equities | Common Stocks, excluding Other Risk |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
8
|
5
|
9
|
| Fair Value, Inputs, Level 3 | Common equities | Other risk investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
39
|
36
|
32
|
| Fair Value, Inputs, Level 3 | Total fixed maturities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
154
|
4
|
5
|
| Fair Value, Inputs, Level 3 | Total fixed maturities | Debt Securities | U.S. government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 3 | Total fixed maturities | Debt Securities | State and local government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 3 | Total fixed maturities | Debt Securities | Foreign government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 3 | Total fixed maturities | Debt Securities | Corporate and other debt |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
4
|
4
|
5
|
| Fair Value, Inputs, Level 3 | Total fixed maturities | Asset-backed Securities | Residential mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 3 | Total fixed maturities | Asset-backed Securities | Commercial mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Fair Value, Inputs, Level 3 | Total fixed maturities | Asset-backed Securities | Other asset-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
150
|
0
|
0
|
| Fair Value, Inputs, Level 3 | Short-term investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
0
|
0
|
0
|
| Carrying (Reported) Amount, Fair Value Disclosure |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
93,463
|
92,709
|
84,475
|
| Equity securities |
1,162
|
1,238
|
1,292
|
| Investments, fair value |
94,625
|
93,947
|
85,767
|
| Long-term debt |
8,387
|
6,897
|
6,895
|
| Carrying (Reported) Amount, Fair Value Disclosure | Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
292
|
419
|
517
|
| Carrying (Reported) Amount, Fair Value Disclosure | Common equities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
870
|
819
|
775
|
| Carrying (Reported) Amount, Fair Value Disclosure | Common equities | Common Stocks, excluding Other Risk |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
831
|
783
|
743
|
| Carrying (Reported) Amount, Fair Value Disclosure | Common equities | Other risk investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
39
|
36
|
32
|
| Carrying (Reported) Amount, Fair Value Disclosure | Total fixed maturities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
91,485
|
82,704
|
82,372
|
| Carrying (Reported) Amount, Fair Value Disclosure | Total fixed maturities | Debt Securities | U.S. government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
44,463
|
43,114
|
46,684
|
| Carrying (Reported) Amount, Fair Value Disclosure | Total fixed maturities | Debt Securities | State and local government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
3,904
|
3,342
|
3,030
|
| Carrying (Reported) Amount, Fair Value Disclosure | Total fixed maturities | Debt Securities | Foreign government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
16
|
17
|
17
|
| Carrying (Reported) Amount, Fair Value Disclosure | Total fixed maturities | Debt Securities | Corporate and other debt |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
21,641
|
19,773
|
18,004
|
| Carrying (Reported) Amount, Fair Value Disclosure | Total fixed maturities | Asset-backed Securities | Residential mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
4,291
|
3,152
|
2,644
|
| Carrying (Reported) Amount, Fair Value Disclosure | Total fixed maturities | Asset-backed Securities | Commercial mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
7,674
|
6,194
|
5,325
|
| Carrying (Reported) Amount, Fair Value Disclosure | Total fixed maturities | Asset-backed Securities | Other asset-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
9,496
|
7,112
|
6,668
|
| Carrying (Reported) Amount, Fair Value Disclosure | Short-term investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
$ 1,978
|
$ 10,005
|
$ 2,103
|