Commitments and Contingencies - Commitments (Details) (USD $)	Jun. 30, 2014 aircraft
Airbus [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Aircraft without Secured Financing Commitments Scheduled for Delivery (in aircraft)	105
Airbus [Member] | 2014 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Aircraft with Secured Financing Commitments Scheduled for Delivery (in aircraft)	4
Airbus [Member] | Fourth Quarter of 2014 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Aircraft without Secured Financing Commitments Scheduled for Delivery (in aircraft)	4
Airbus [Member] | 2015 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Aircraft without Secured Financing Commitments Scheduled for Delivery (in aircraft)	11
Aircraft and Related Flight Equipment [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year	$ 350,000,000
Unrecorded Unconditional Purchase Obligation, Due in 2015	658,000,000
Unrecorded Unconditional Purchase Obligation, Due in 2016	601,000,000
Unrecorded Unconditional Purchase Obligation, Due in 2017	757,000,000
Unrecorded Unconditional Purchase Obligation, Due in 2018	615,000,000
Unrecorded Unconditional Purchase Obligation, Due in 2019 and beyond	$ 2,207,000,000
V2500 SelectOne Engine [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of spare aircraft engines ordered (in aircraft engine)	6
PurePower PW1100G-JM Engine [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of spare aircraft engines ordered (in aircraft engine)	9