XML 34 R23.htm IDEA: XBRL DOCUMENT v3.10.0.1

Basis of Presentation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Aircraft rentals	$ 40	$ 53	$ 80	$ 107

X

- Definition

Expenses incurred related to the lease of aircraft from outside third parties that are used in the entity's business operations.

+ References

No definition available.

+ Details

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

X

- References

No definition available.

+ Details

Name:	us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration