Commitments and Contingencies - Commitments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015 aircraft
Aircraft [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Operating Leases of Lessee, Number of Leased Assets	61
Spare Engines [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Operating Leases of Lessee, Number of Leased Assets	10
Aircraft [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Delivered Aircraft with Secured Debt Financing Commitments	5
Property, Plant and Equipment, Useful Life	25 years
Major Spare Rotable Parts, Avionics, and Assemblies [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Property, Plant and Equipment, Salvage Value, Percentage	10.00%
Airbus A320 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of aircraft held	70
Airbus [Member] \| 2015 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Aircraft with Secured Financing Commitments Scheduled for Delivery (in aircraft)	6
Number of Aircraft Scheduled for Delivery (in aircraft)	9
Airbus [Member] \| 2015-2021 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Aircraft without Secured Financing Commitments Scheduled for Delivery (in aircraft)	90
Third Party Lessor [Member] \| 2015-2016 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Direct Leased Aircraft Ordered From A Third Party	5
Aircraft and Related Flight Equipment [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year	422.7
Unrecorded Unconditional Purchase Obligation, Due in 2016	604.0
Unrecorded Unconditional Purchase Obligation, Due in 2017	763.4
Unrecorded Unconditional Purchase Obligation, Due in 2018	621.4
Unrecorded Unconditional Purchase Obligation, Due in 2019	711.1
Unrecorded Unconditional Purchase Obligation, Due in 2020 and beyond	1,525.3
V2500 SelectOne Engine [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of spare aircraft engines ordered (in aircraft engine)	5
PurePower PW1100G-JM Engine [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of spare aircraft engines ordered (in aircraft engine)	9
Secured Debt [Member] \| Aircraft and Related Flight Equipment [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Debt financing commitments	231

Face/par value in contract for future debt financing commitments

No definition available.

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- Definition

Number of Aircraft Held

+ References

No definition available.

+ Details

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- Definition

Number of Aircraft Scheduled for Delivery

+ References

No definition available.

+ Details

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- Definition

Number of Aircraft without Secured Financing Commitments Scheduled for Delivery

+ References

No definition available.

+ Details

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- Definition

Number of Aircraft with Secured Debt Financing Commitments Scheduled for Delivery

+ References

No definition available.

+ Details

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- Definition

Number of Delivered Aircraft with Secured Debt Financing Commitments

+ References

No definition available.

+ Details

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- Definition

Number of Direct Leased Aircraft Ordered From A Third Party

+ References

No definition available.

+ Details

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- Definition

Number of Spare Aircraft Engines Ordered

+ References

No definition available.

+ Details

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- Definition

Operating Leases of Lessee, Number of Leased Assets

+ References

No definition available.

+ Details

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- Definition

Stated as a percentage, the estimated or actual value of the asset at the end of its useful life or when it is no longer serviceable (cannot be used for its original purpose) divided by its [historical] capitalized cost.

+ References

No definition available.

+ Details

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- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308

+ Details

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the remainder of the fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

+ Details

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- Details

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