Summary of Significant Accounting Policies Details (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ (5,472)	$ (4,164)
Property and equipment, net of accumulated depreciation and amortization	20,223	20,307
Flight Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	21,001	20,312
Property, Plant and Equipment, Useful Life, Minimum	21
Property, Plant and Equipment, Useful Life, Maximum	30
Ground Property and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	3,256	3,123
Property, Plant and Equipment, Useful Life, Minimum	3
Property, Plant and Equipment, Useful Life, Maximum	40
Flight and Ground Equipment Under Capital Lease [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,127	988
Property, Plant and Equipment, Estimated Useful Lives	Shorter of lease term or estimated useful life
Assets Constructed for Others [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	234	0
Property, Plant and Equipment, Useful Life, Maximum	30
Advance Payments for Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 77	$ 48
Software and Software Development Costs [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	3
Property, Plant and Equipment, Useful Life, Maximum	7