Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2013

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

(in millions)	December 31, 2013			Level 1		Level 2			Level 3		Valuation Technique
Cash equivalents	$	2,487		$	2,487	$	—		$	—	(a)
Short-term investments	959			959		—			—		(a)
Restricted cash equivalents and investments	118			118		—			—		(a)
Long-term investments	109			80		29			—		(a)(b)
Hedge derivatives, net
Fuel hedge contracts	314			16		298			—		(a)(b)
Interest rate contracts	(67		)	—		(67		)	—		(a)(b)
Foreign currency exchange contracts	257			—		257			—		(a)

(in millions)	December 31, 2012			Level 1		Level 2			Level 3		Valuation Technique
Cash equivalents	$	2,176		$	2,176	$	—		$	—	(a)
Short-term investments	958			958		—			—		(a)
Restricted cash equivalents and investments	344			344		—			—		(a)
Long-term investments	208			100		27			81		(a)(b)
Hedge derivatives, net
Fuel hedge contracts	249			27		222			—		(a)(b)
Interest rate contracts	(66		)	—		(66		)	—		(a)(b)
Foreign currency exchange contracts	123			—		123			—		(a)

⁽¹⁾  See Note 11, “Employee Benefit Plans”, for fair value of benefit plan assets.