Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Consolidated Statements Of Cash Flows [Abstract]
Net Cash Provided by (used for) Operating Activities	$ 1,067	$ 708
Cash Flow from Investing Activities:
Capital expenditures, including aircraft lease deposits	(238)	(359)
Net (increase) decrease in short-term investments	(726)	(1,185)
Net (increase) decrease in restricted cash and short-term investments	(33)	(5)
Proceeds from sale of equipment and property	12	(6)
Net cash used for investing activities	(985)	(1,555)
Cash Flow from Financing Activities:
Payments on long-term debt and capital lease obligations	(314)	(323)
Proceeds from:
Issuance of debt		1,164
Sale leaseback transactions	324	125
Other		(1)
Net cash provided by financing activities	10	965
Net increase (decrease) in cash	92	118
Cash at beginning of period	283	168
Cash at end of period	$ 375	$ 286