Equipment held for lease (Detail) - Insurance and Other [Member] - USD ($) $ in Millions |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Property Subject to or Available for Operating Lease [Line Items] | ||
| Equipment held for lease, gross | $ 20,617 | $ 13,775 |
| Equipment held for lease, accumulated depreciation | (6,319) | (3,608) |
| Equipment held for lease, net | 14,298 | 10,167 |
| Railcars [Member] | ||
| Property Subject to or Available for Operating Lease [Line Items] | ||
| Equipment held for lease, gross | 8,862 | 8,352 |
| Aircraft [Member] | ||
| Property Subject to or Available for Operating Lease [Line Items] | ||
| Equipment held for lease, gross | 7,376 | 1,456 |
| Other Equipment Held for Lease [Member] | ||
| Property Subject to or Available for Operating Lease [Line Items] | ||
| Equipment held for lease, gross | $ 4,379 | $ 3,967 |