CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net Income	$ 271.7	$ 180.5
Adjustments to reconcile net income to net cash provided by operating activities:
Fleet transition expenses	0	38.9
Depreciation and amortization	195.4	184.2
Stock-based compensation and other	7.8	9.5
Changes in certain assets and liabilities:
Changes in fair values of open fuel hedge contracts	28.1	53.1
Changes in deferred income taxes	101.3	101.9
Increase in air traffic liability	94.2	118.7
Increase (decrease) in deferred revenue	13.2	(9.5)
Increase in other long-term liabilities	5.7	42.3
Pension contribution	(35.4)	(33.4)
Other - net	(44.7)	(77.4)
Net cash provided by operating activities	637.3	608.8
Property and equipment additions:
Aircraft and aircraft purchase deposits	(297.6)	(260.3)
Other flight equipment	(12.8)	(18.4)
Other property and equipment	(29.3)	(15.8)
Total property and equipment additions	(339.7)	(294.5)
Assets constructed for others (Terminal 6 at LAX)	(65.3)	(80.4)
Purchases of marketable securities	(810.8)	(781.7)
Sales and maturities of marketable securities	701.5	697.2
Proceeds from disposition of assets and changes in restricted deposits	0.8	20.8
Net cash used in investing activities	(513.5)	(438.6)
Cash flows from financing activities:
Proceeds from issuance of long-term debt	0	106.5
Long-term debt payments	(239.9)	(248.3)
Proceeds from sale-leaseback transactions	49.3	0
Common stock repurchases	(51.7)	(61.6)
Proceeds and tax benefit from issuance of common stock	22.5	16.7
Other financing activities	21.3	(5.5)
Net cash used in financing activities	(198.5)	(192.2)
Net decrease in cash and cash equivalents	(74.7)	(22.0)
Cash and cash equivalents at beginning of year	102.2	89.5
Cash and cash equivalents at end of the period	27.5	67.5
Cash paid during the period for:
Interest (net of amount capitalized)	40.2	66.0
Income taxes	49.3	2.2
Non-cash transactions:
Assets constructed related to Terminal 6 at LAX	$ 1.6	$ 10.5