Retirement-Related Benefits - All Retirement Plans Cost (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
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| Retirement-Related Benefits | ||
| Defined benefit and contribution pension plans - cost | $ 738 | $ 664 |
| Nonpension postretirement plans - cost | 51 | 61 |
| Total | $ 788 | $ 725 |
| Year-to-year percent change, defined benefit and contribution pension plans cost (as a percent) | 11.10% | |
| Year-to-year percent change, nonpension postretirement plans cost (as a percent) | (17.20%) | |
| Year-to-year percent change, total (as a percent) | 8.70% | |
| X | ||||||||||
- Definition The percentage change from year to year in the nonpension postretirement plans cost. No definition available.
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- Definition The percentage change from year to year in the defined benefit and contribution pension plans and the nonpension postretirement plans cost. No definition available.
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- Definition The percentage change from year to year in the defined benefit and contribution pension plans cost. No definition available.
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- References No definition available.
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- Definition Amount of cost (reversal of cost) for other postretirement benefits. Excludes pension benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of cost (reversal of cost) for pension and other postretirement benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of cost (reversal of cost) for pension benefits. Excludes other postretirement benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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