Fair Value - Composition of Investment Portfolio by Major Security Type (Detail) - USD ($)
$ in Millions |
Mar. 31, 2026 |
Dec. 31, 2025 |
Mar. 31, 2025 |
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
$ 89,958
|
$ 92,871
|
$ 79,696
|
| Equity securities |
4,173
|
4,502
|
3,968
|
| Investments, fair value |
94,131
|
97,373
|
83,664
|
| Fair value |
7,728
|
6,345
|
6,247
|
| Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
240
|
404
|
584
|
| Common equities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
3,933
|
4,098
|
3,384
|
| Common equities | Common Stocks, excluding Other Risk |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
3,896
|
4,062
|
3,353
|
| Common equities | Other risk investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
37
|
36
|
31
|
| Total fixed maturities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
87,832
|
82,866
|
77,101
|
| Total fixed maturities | U.S. government |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
44,417
|
43,298
|
44,318
|
| 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 |
3,087
|
3,303
|
2,604
|
| 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
|
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 |
20,986
|
19,991
|
16,016
|
| Total fixed maturities | Residential mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
4,136
|
3,175
|
2,183
|
| Total fixed maturities | Commercial mortgage-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
6,991
|
5,973
|
4,825
|
| Total fixed maturities | Other asset-backed |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
8,199
|
7,109
|
7,139
|
| 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 |
44,417
|
43,298
|
44,318
|
| 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 |
3,087
|
3,303
|
2,604
|
| 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
|
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 |
20,986
|
19,991
|
16,016
|
| 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 |
4,136
|
3,175
|
2,183
|
| 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 |
6,991
|
5,973
|
4,825
|
| 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 |
8,199
|
7,109
|
7,139
|
| Short-term investments |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
2,126
|
10,005
|
2,595
|
| Fair Value, Inputs, Level 1 |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
46,489
|
53,108
|
46,913
|
| Equity securities |
3,891
|
4,057
|
3,344
|
| Investments, fair value |
50,380
|
57,165
|
50,257
|
| 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 |
3,891
|
4,057
|
3,344
|
| 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 |
3,891
|
4,057
|
3,344
|
| 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 |
44,417
|
43,298
|
44,318
|
| 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 |
44,417
|
43,298
|
44,318
|
| 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 |
2,072
|
9,810
|
2,595
|
| Fair Value, Inputs, Level 2 |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
43,465
|
39,759
|
32,778
|
| Equity securities |
191
|
344
|
524
|
| Investments, fair value |
43,656
|
40,103
|
33,302
|
| Fair value |
7,728
|
6,345
|
6,247
|
| Fair Value, Inputs, Level 2 | Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
191
|
344
|
524
|
| 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 |
43,411
|
39,564
|
32,778
|
| 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 |
3,087
|
3,303
|
2,604
|
| 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
|
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 |
20,982
|
19,987
|
16,011
|
| 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 |
4,136
|
3,175
|
2,183
|
| 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 |
6,991
|
5,973
|
4,825
|
| 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 |
8,199
|
7,109
|
7,139
|
| 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 |
54
|
195
|
0
|
| Fair Value, Inputs, Level 3 |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Total available-for-sale securities |
4
|
4
|
5
|
| Equity securities |
91
|
101
|
100
|
| Investments, fair value |
95
|
105
|
105
|
| 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 |
42
|
41
|
40
|
| 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 |
5
|
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 |
37
|
36
|
31
|
| 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 |
4
|
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 |
0
|
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 |
90,534
|
92,709
|
80,349
|
| Equity securities |
1,098
|
1,238
|
1,382
|
| Investments, fair value |
91,632
|
93,947
|
81,731
|
| Long-term debt |
8,386
|
6,897
|
6,894
|
| Carrying (Reported) Amount, Fair Value Disclosure | Nonredeemable preferred stocks |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
259
|
419
|
608
|
| Carrying (Reported) Amount, Fair Value Disclosure | Common equities |
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
| Equity securities |
839
|
819
|
774
|
| 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 |
802
|
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 |
37
|
36
|
31
|
| 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 |
88,408
|
82,704
|
77,754
|
| 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 |
44,676
|
43,114
|
44,523
|
| 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 |
3,135
|
3,342
|
2,688
|
| 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
|
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 |
20,994
|
19,773
|
16,047
|
| 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 |
4,127
|
3,152
|
2,172
|
| 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 |
7,228
|
6,194
|
5,144
|
| 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 |
8,232
|
7,112
|
7,164
|
| 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 |
$ 2,126
|
$ 10,005
|
$ 2,595
|