Commitments and Contingencies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013
Capital Addition Purchase Commitments [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Aircraft Purchase Commitments, Total	$ 9,855
B-737-900ER [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required	99
B-787-8 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required	18
A330-300 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required	10
CRJ-900 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required	37
A321-200 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required	30
B-717-200 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Other Aircraft Commitments	88
Number of Aircraft Acquired	1