Fair Value - Composition of Investment Portfolio by Major Security Type (Detail) - USD ($)
$ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
Sep. 30, 2025 |
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
$ 94,372
|
$ 92,871
|
$ 90,024
|
| Equity securities |
4,825
|
4,502
|
4,485
|
| Investments, fair value |
99,197
|
97,373
|
94,509
|
| Fair value |
7,345
|
6,345
|
6,398
|
| Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
193
|
404
|
438
|
| Common equities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
4,632
|
4,098
|
4,047
|
| Common equities | Common Stocks, excluding Other Risk |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
4,593
|
4,062
|
4,013
|
| Common equities | Other risk investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
39
|
36
|
34
|
| Total fixed maturities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
92,247
|
82,866
|
88,509
|
| Total fixed maturities | U.S. government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
41,594
|
43,298
|
51,339
|
| 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 |
3,835
|
3,303
|
3,275
|
| Total fixed maturities | Foreign government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
|
17
|
16
|
| 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 |
23,275
|
19,991
|
18,817
|
| Total fixed maturities | Residential mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
4,559
|
3,175
|
3,000
|
| Total fixed maturities | Commercial mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
7,909
|
5,973
|
5,686
|
| Total fixed maturities | Other asset-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
11,075
|
7,109
|
6,376
|
| 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 |
41,594
|
43,298
|
51,339
|
| 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 |
3,835
|
3,303
|
3,275
|
| 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 |
|
17
|
16
|
| 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 |
23,275
|
19,991
|
18,817
|
| 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 |
4,559
|
3,175
|
3,000
|
| 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 |
7,909
|
5,973
|
5,686
|
| 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 |
11,075
|
7,109
|
6,376
|
| Short-term investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
2,125
|
10,005
|
1,515
|
| Fair Value, Inputs, Level 1 |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
43,676
|
53,108
|
52,753
|
| Equity securities |
4,585
|
4,057
|
4,004
|
| Investments, fair value |
48,261
|
57,165
|
56,757
|
| 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 |
4,585
|
4,057
|
4,004
|
| 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 |
4,585
|
4,057
|
4,004
|
| 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 |
41,594
|
43,298
|
51,339
|
| 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 |
41,594
|
43,298
|
51,339
|
| 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
|
| 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 |
2,082
|
9,810
|
1,414
|
| Fair Value, Inputs, Level 2 |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
50,538
|
39,759
|
37,266
|
| Equity securities |
140
|
344
|
378
|
| Investments, fair value |
50,678
|
40,103
|
37,644
|
| Fair value |
7,345
|
6,345
|
6,398
|
| Fair Value, Inputs, Level 2 | Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
140
|
344
|
378
|
| 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 |
50,495
|
39,564
|
37,165
|
| 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 |
3,835
|
3,303
|
3,275
|
| 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 |
|
17
|
16
|
| 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 |
23,266
|
19,987
|
18,812
|
| 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 |
4,559
|
3,175
|
3,000
|
| 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 |
7,909
|
5,973
|
5,686
|
| 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 |
10,926
|
7,109
|
6,376
|
| 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 |
43
|
195
|
101
|
| Fair Value, Inputs, Level 3 |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
158
|
4
|
5
|
| Equity securities |
100
|
101
|
103
|
| Investments, fair value |
258
|
105
|
108
|
| 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 |
53
|
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
|
43
|
| 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
|
34
|
| 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 |
158
|
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
|
| 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 |
9
|
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 |
149
|
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 |
97,844
|
92,709
|
89,762
|
| Equity securities |
1,121
|
1,238
|
1,262
|
| Investments, fair value |
98,965
|
93,947
|
91,024
|
| Long-term debt |
8,389
|
6,897
|
6,896
|
| Carrying (Reported) Amount, Fair Value Disclosure | Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
212
|
419
|
454
|
| Carrying (Reported) Amount, Fair Value Disclosure | Common equities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
909
|
819
|
808
|
| 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 |
870
|
783
|
774
|
| 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
|
34
|
| 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 |
95,719
|
82,704
|
88,247
|
| 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 |
43,865
|
43,114
|
51,021
|
| 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 |
3,988
|
3,342
|
3,320
|
| 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 |
|
17
|
16
|
| 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 |
23,856
|
19,773
|
18,621
|
| 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 |
4,654
|
3,152
|
2,979
|
| 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 |
8,174
|
6,194
|
5,916
|
| 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 |
11,182
|
7,112
|
6,374
|
| 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 |
$ 2,125
|
$ 10,005
|
$ 1,515
|