Special Items (Details)	3 Months Ended	12 Months Ended
Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Unusual or Infrequent Item, or Both [Line Items]
Impairment of Long-Lived Assets Held-for-use						$ 0	$ 319,000,000	$ 0
Special Items - E190 Fleet Transition						6,000,000	362,000,000	0
Special Items - Union Contract Costs						8,000,000	73,000,000	0
Special Items	$ 2,000,000	$ 12,000,000	$ 4,000,000	$ 112,000,000	$ 319,000,000	$ 14,000,000	$ 435,000,000	$ 0
Number of options converted A220							10

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration