Income Taxes (Tables)

12 Months Ended

Dec. 31, 2011

Income Taxes

Schedule of income tax provision for continuing operations

In millions	2011		2010			2009
Current:
Federal	$	1,807	$	1,884		$	1,761
State	338		344			397
	2,145		2,228			2,158
Deferred:
Federal	101		(44		)	38
State	12		(5		)	4
	113		(49		)	42
Total	$	2,258	$	2,179		$	2,200

Reconciliation of the statutory income tax rate to the Company's effective income tax rate for continuing operations

	2011		2010		2009
Statutory income tax rate	35.0	%	35.0	%	35.0	%
State income taxes, net of federal tax benefit	3.9		4.1		4.5
Other	0.4		0.6		0.6
Subtotal	39.3		39.7		40.1
Recognition of previously unrecognized tax benefits	—		(0.8	)	(2.8	)
Effective income tax rate	39.3	%	38.9	%	37.3	%

Summary of the significant components of the Company's deferred tax assets and liabilities

In millions	2011			2010
Deferred tax assets:
Lease and rents	$	325		$	325
Inventories	77			69
Employee benefits	253			261
Allowance for doubtful accounts	112			96
Retirement benefits	114			99
Net operating losses	6			6
Other	315			307
Total deferred tax assets	1,202			1,163
Deferred tax liabilities:
Depreciation and amortization	(4,552		)	(4,307		)
Net deferred tax liabilities	$	(3,350	)	$	(3,144	)

Schedule of net deferred tax assets (liabilities)

In millions	2011			2010
Deferred tax assets—current	$	503		$	511
Deferred tax liabilities—noncurrent	(3,853		)	(3,655		)
Net deferred tax liabilities	$	(3,350	)	$	(3,144	)

Reconciliation of the beginning and ending amount of unrecognized tax benefits

In millions	2011			2010			2009
Beginning balance	$	35		$	61		$	257
Additions based on tax positions related to the current year	3			1			1
Additions based on tax positions related to prior years	13			2			12
Reductions for tax positions of prior years	—			(10		)	(6		)
Expiration of statutes of limitation	(7		)	(16		)	(155		)
Settlements	(6		)	(3		)	(48		)
Ending balance	$	38		$	35		$	61