Business segment data - Narrative (Detail) - USD ($)
$ in Millions |
|
3 Months Ended |
12 Months Ended |
Dec. 31, 2018 |
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
| Segment Reporting Information [Line Items] |
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| Revenues |
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$ 63,714
|
$ 63,450
|
$ 62,200
|
$ 58,473
|
$ 58,800
|
$ 59,507
|
$ 57,256
|
$ 64,370
|
$ 247,837
|
$ 239,933
|
$ 215,114
|
| Sales, Service and Leasing Revenues [Member] |
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| Segment Reporting Information [Line Items] |
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| Revenues |
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$ 139,100
|
$ 132,800
|
$ 125,600
|
| United States [Member] | Geographic Concentration [Member] | Sales, Service and Leasing Revenues [Member] |
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| Segment Reporting Information [Line Items] |
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| Concentration percentage |
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84.00%
|
85.00%
|
85.00%
|
| United States [Member] | Geographic Concentration [Member] | Property, Plant and Equipment and Equipment Held for Lease [Member] |
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| Segment Reporting Information [Line Items] |
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| Concentration percentage |
89.00%
|
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| Walmart Stores, Inc. [Member] | Sales, Service and Leasing Revenues [Member] |
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| Segment Reporting Information [Line Items] |
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| Revenues |
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|
|
$ 13,000
|
$ 14,000
|
$ 14,000
|
| Railroad, Utilities and Energy [Member] |
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| Segment Reporting Information [Line Items] |
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| Revenues |
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|
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$ 43,673
|
$ 40,005
|
$ 37,447
|
| Railroad, Utilities and Energy [Member] | United States [Member] | Geographic Concentration [Member] | Revenues [Member] |
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| Segment Reporting Information [Line Items] |
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| Concentration percentage |
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|
|
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96.00%
|
95.00%
|
95.00%
|