Summary of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Ownership Interest	50.00%
Accumulated Depreciation and Amortization	$ (7,792,000,000)	$ (6,656,000,000)
Amortization of Capitalized Computer Software	110,000,000	76,000,000	64,000,000
Net Book Value of Capitalized Computer Software	383,000,000	344,000,000
Goodwill	9,794,000,000	9,794,000,000
Identifiable intangibles, net of accumulated amortization	4,658,000,000	4,679,000,000
Depreciation, Nonproduction	1,500,000,000	1,400,000,000	1,400,000,000
Advertising Expense	222,000,000	235,000,000	214,000,000
Flight and Ground Equipment Under Capital Lease [Member]
Property, Plant and Equipment [Line Items]
Long-Lived Assets, Estimated Useful Lives	Shorter of lease term or estimated useful life
Accumulated Depreciation and Amortization	$ 657,000,000	$ 653,000,000
Minimum [Member]
Property, Plant and Equipment [Line Items]
Long-Lived Assets, Estimated Useful Lives	3
Maximum [Member]
Property, Plant and Equipment [Line Items]
Long-Lived Assets, Estimated Useful Lives	7
Maximum [Member]
Property, Plant and Equipment [Line Items]
Spare Parts Residual Value	10.00%
Minimum [Member]
Property, Plant and Equipment [Line Items]
Spare Parts Residual Value	5.00%
Future revenue increase [Member]
Property, Plant and Equipment [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements, Allocation to Specific Unit of Accounting, Effect of Changes, Selling Price	100
Current period change [Member]
Property, Plant and Equipment [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements, Allocation to Specific Unit of Accounting, Effect of Changes, Selling Price	10