Assumed Health Care Plan Post-Age

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- Definition

Assumed Health Care Plan Pre-Age

+ References

No definition available.

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- Definition

Defined Benefit Plan, Percent Change Assumed In Health Care Cost Trend Metric

+ References

No definition available.

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- Definition

Percent Of Amount Above Annual PreTax Profit For Profit Sharing Payout

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No definition available.

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- Definition

Percent Of Amount Above Threshold For Profit Sharing Payout

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- Definition

Percent Of Annual PreTax Profit For Profit Sharing Payout

+ References

No definition available.

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- Definition

Percent Of Threshold Amount For Profit Sharing Payout

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- Definition

Profit Sharing Threshold

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No definition available.

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- Definition

Unfunded Liability, Defined Benefit Plan, Interest Rate

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No definition available.

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of cost (credit) included in accumulated other comprehensive (income) loss expected to be recognized in net periodic benefit cost (credit) for fiscal year following most recent annual statement of financial position.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (s)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Amount of contributions expected to be received by defined benefit plan from employer in next fiscal year following latest fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(i)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Ultimate trend rate for health care cost for defined benefit postretirement plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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- Definition

Amount of labor-related expenses classified as other.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.4)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Employee Benefit Plans - Narrative (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
Employee Benefit Plans - Narrative (Details) - USD ($)	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 01, 2017
Defined Benefit Plan Disclosure
Discount rate for amortization of unfunded liability for frozen defined benefit plan (percent)			8.85%
Estimated funding by employer in next fiscal year	$ 500,000,000		$ 500,000,000
Defined contribution plan costs			$ 875,000,000	$ 733,000,000	$ 592,000,000
Assumed healthcare plan pre age			65 years
Assumed healthcare plan post age			65 years
Amount of net actuarial loss that will be amortized from AOCI in next fiscal year	$ 277,000,000		$ 277,000,000
Ultimate healthcare cost trend rate (percent)	5.00%		5.00%
Percent change assumed In healthcare cost trend metric			1.00%
Weighted average expected long-term rate of return on plan assets (percent)			8.96%	8.94%	8.94%
Profit sharing			$ 1,065,000,000	$ 1,115,000,000	$ 1,490,000,000
Percent of threshold amount for profit sharing payout	10.00%
Profit sharing threshold						$ 2,500,000,000.0
Percent of amount above threshold for profit sharing payout	20.00%
Delta Pilots
Defined Benefit Plan Disclosure
Percent of threshold amount for profit sharing payout		10.00%		10.00%
Profit sharing threshold		$ 2,500,000,000.0		$ 2,500,000,000.0
Percent of amount above threshold for profit sharing payout		20.00%		20.00%
Merit, Ground, Flight Attendant Employees
Defined Benefit Plan Disclosure
Percent of annual pre-tax profit for profit sharing payout		10.00%		10.00%
Percent of year-over-year increase in annual pre-tax profit for profit sharing payout		20.00%		20.00%
Growth-seeking assets \| Maximum
Defined Benefit Plan Disclosure
Plan assets, target allocations (percent)	50.00%		50.00%
Growth-seeking assets \| Minimum
Defined Benefit Plan Disclosure
Plan assets, target allocations (percent)	40.00%		40.00%
Income-generating assets \| Maximum
Defined Benefit Plan Disclosure
Plan assets, target allocations (percent)	30.00%		30.00%
Income-generating assets \| Minimum
Defined Benefit Plan Disclosure
Plan assets, target allocations (percent)	20.00%		20.00%
Risk-diversifying assets \| Maximum
Defined Benefit Plan Disclosure
Plan assets, target allocations (percent)	30.00%		30.00%
Risk-diversifying assets \| Minimum
Defined Benefit Plan Disclosure
Plan assets, target allocations (percent)	25.00%		25.00%