Income taxes - Deferred taxes (Detail) - USD ($) $ in Millions |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Deferred tax liabilities: | ||
| Investments - unrealized appreciation and cost basis differences | $ 17,765 | $ 24,251 |
| Deferred charges reinsurance assumed | 2,970 | 3,226 |
| Property, plant and equipment | 28,279 | 26,671 |
| Goodwill and other intangible assets | 7,199 | 7,204 |
| Other deferred tax liabilities | 3,187 | 3,216 |
| Deferred tax liabilities | 59,400 | 64,568 |
| Deferred tax assets: | ||
| Unpaid losses and loss adjustment expenses | (1,238) | (1,231) |
| Unearned premiums | (767) | (345) |
| Accrued liabilities | (1,956) | (2,501) |
| Regulatory liabilities | (1,673) | (1,707) |
| Other deferred tax assets | (3,263) | (2,602) |
| Deferred tax assets | (8,897) | (8,386) |
| Net deferred tax liability | $ 50,503 | $ 56,182 |