Employee Benefit Plans - Narrative (Details) - USD ($)
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9 Months Ended |
12 Months Ended |
27 Months Ended |
Sep. 30, 2017 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2019 |
| Defined Benefit Plan Disclosure |
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| Discount rate for 17-year amortization period of unfunded liability for frozen defined benefit plan (percent) |
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8.85%
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| Estimated funding by employer in next fiscal year |
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$ 500,000,000
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$ 500,000,000
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| Defined contribution plan costs |
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$ 991,000,000
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$ 926,000,000
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$ 875,000,000
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| Assumed healthcare plan pre age |
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65 years
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| Assumed healthcare plan post age |
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65 years
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| Amount of net actuarial loss that will be amortized from AOCI in next fiscal year |
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$ 333,000,000
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$ 333,000,000
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| Weighted average expected long-term rate of return on plan assets (percent) |
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8.97%
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8.97%
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8.96%
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| Percent change assumed In healthcare cost trend metric |
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1.00%
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| Profit sharing |
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$ 1,643,000,000
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$ 1,301,000,000
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$ 1,065,000,000
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| Percent of threshold amount for profit sharing payout |
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10.00%
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| Profit sharing threshold |
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$ 2,500,000,000
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|
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$ 2,500,000,000
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| Percent of amount above threshold for profit sharing payout |
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|
|
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20.00%
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| Common stock |
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| Defined Benefit Plan Disclosure |
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| Employer contribution to certain defined pension plans |
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|
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$ 350,000,000
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$ 350,000,000
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| Delta Pilots |
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| Defined Benefit Plan Disclosure |
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| Percent of threshold amount for profit sharing payout |
10.00%
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| Profit sharing threshold |
$ 2,500,000,000
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| Percent of amount above threshold for profit sharing payout |
20.00%
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| Merit, Ground, Flight Attendant Employees |
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| Defined Benefit Plan Disclosure |
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| Percent of annual pre-tax profit for profit sharing payout |
10.00%
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| Percent of year-over-year increase in annual pre-tax profit for profit sharing payout |
20.00%
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| Growth-seeking assets | Minimum |
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| Defined Benefit Plan Disclosure |
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| Plan assets, target allocations (percent) |
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30.00%
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30.00%
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| Growth-seeking assets | Maximum |
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| Defined Benefit Plan Disclosure |
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| Plan assets, target allocations (percent) |
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50.00%
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50.00%
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| Income-generating assets | Minimum |
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| Defined Benefit Plan Disclosure |
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| Plan assets, target allocations (percent) |
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25.00%
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25.00%
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| Income-generating assets | Maximum |
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| Defined Benefit Plan Disclosure |
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| Plan assets, target allocations (percent) |
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35.00%
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35.00%
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| Risk-diversifying assets | Minimum |
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| Defined Benefit Plan Disclosure |
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| Plan assets, target allocations (percent) |
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30.00%
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30.00%
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| Risk-diversifying assets | Maximum |
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| Defined Benefit Plan Disclosure |
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| Plan assets, target allocations (percent) |
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40.00%
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40.00%
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