DETAIL OF OTHER FINANCIAL STATEMENT CAPTIONS

Receivables

Receivables consisted of the following at December 31 (in millions):



	2011			2010
Airline traffic receivables	$	66.5		$	53.6
Mileage Plan receivables	40.2			37.9
Other receivables	30.5			29.5
Allowance for doubtful accounts	(0.8		)	(0.9		)
	$	136.4		$	120.1

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following at December 31 (in millions):



	2011		2010
Prepaid aircraft rent	$	29.5	$	42.5
Prepaid engine maintenance	30.5		28.7
Prepaid credit card and travel agent commissions	9.8		8.9
Prepaid fuel	4.0		12.6
Other	19.2		14.0
	$	93.0	$	106.7

Other Assets

Other assets consisted of the following at December 31 (in millions):



	2011		2010
Restricted deposits (primarily restricted investments)	$	83.0	$	83.6
Prepaid aircraft rent	12.8		21.6
Deferred costs and other	32.0		31.1
	$	127.8	$	136.3

Deferred costs and other includes deferred financing costs, lease deposits and other items.

Other Accrued Liabilities

Other accrued liabilities consisted of the following at December 31 (in millions):



	2011		2010
Mileage Plan current liabilities	$	271.4	$	278.0
Property and transportation taxes	71.5		67.0
Fuel hedge contracts	10.3		—
Interest rate swaps	5.2		6.0
Postretirement medical benefits liability	4.1		4.9
Pension liability (nonqualified plans)	2.2		2.3
Other	148.6		143.0
	$	513.3	$	501.2

Other consists of accruals for ground operations, facilities rent, maintenance, and fuel, among other items.