Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Accumulated Depreciation and Amortization	$ (7,792)	$ (6,656)
Property and equipment, net of accumulated depreciation and amortization	21,854	20,713
Flight Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	23,373	21,481
Long-Lived Assets, Estimated Useful Lives	21-30 years
Ground Property and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	4,596	4,254
Long-Lived Assets, Estimated Useful Lives	3-40 years
Flight and Ground Equipment Under Capital Lease [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,296	1,381
Accumulated Depreciation and Amortization	657	653
Long-Lived Assets, Estimated Useful Lives	Shorter of lease term or estimated useful life
Advance Payments for Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 381	$ 253