CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities:
Net Income	$ 40.8	$ 74.2
Adjustments to reconcile net income to net cash provided by operating activities:
Fleet transition expenses	0	10.1
Depreciation and amortization	63.7	60.3
Stock-based compensation and other	5.3	6.7
Changes in certain assets and liabilities:
Changes in fair values of open fuel hedge contracts	(24.9)	(89.2)
Changes in deferred income taxes	25.8	43.2
Increase in air traffic liability	164.6	163.0
Decrease in deferred revenue	(4.0)	(15.7)
Increase (decrease) in other long-term liabilities	17.6	(3.3)
Pension contribution	(11.8)	(11.1)
Other - net	(93.8)	(119.4)
Net cash provided by operating activities	183.3	118.8
Property and equipment additions:
Aircraft and aircraft purchase deposits	(80.9)	(139.3)
Other flight equipment	(2.3)	(4.9)
Other property and equipment	(14.9)	(4.9)
Total property and equipment additions	(98.1)	(149.1)
Assets constructed for others (Terminal 6 at LAX)	(23.6)	0
Purchases of marketable securities	(240.1)	(181.6)
Sales and maturities of marketable securities	188.1	314.0
Proceeds from disposition of assets and changes in restricted deposits	0.3	(17.1)
Net cash used in investing activities	(173.4)	(33.8)
Cash flows from financing activities:
Long-term debt payments	(59.1)	(89.2)
Common stock repurchases	(8.8)	(26.3)
Proceeds and tax benefit from issuance of common stock	3.8	8.3
Other financing activities	0.2	(7.1)
Net cash used in financing activities	(63.9)	(114.3)
Net decrease in cash and cash equivalents	(54.0)	(29.3)
Cash and cash equivalents at beginning of year	102.2	89.5
Cash and cash equivalents at end of year	48.2	60.2
Cash paid (refunded) during the year for:
Interest (net of amount capitalized)	15.6	25.1
Income taxes	(2.5)	0
Non-cash transactions:
Assets constructed related to Terminal 6 at LAX	$ 50.9	$ 0