Merger and Related Matters (Allocation of Consideration Transferred) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 09, 2013	Dec. 31, 2012
Business Combinations [Abstract]
Cash		$ 206
Short-term investments		3,517
Other current assets		1,459
Operating property and equipment		5,543
Goodwill	4,086	4,086	0
Identifiable intangibles		1,501
Other noncurrent assets		122
Long-term debt and capital leases, including current portion		(6,026)
Air traffic liability		(1,417)
Frequent flyer liability		(1,256)
Other liabilities assumed		(3,143)
Total purchase price		$ 4,592