Commitments and Contingencies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013
Capital Addition Purchase Commitments [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Aircraft Purchase Commitments, Total	$ 7,695
B-737-900ER [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required	100
B-787-8 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required	18
B-717-200 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Other Aircraft Commitments	88
A319-100 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number Of Aircraft Not Included In Aircraft Purchase Commitments	5
A320-200 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number Of Aircraft Not Included In Aircraft Purchase Commitments	2
Bombardier Aerospace [Member] | CRJ-900 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required	40