Income Taxes (Tables)

12 Months Ended

Dec. 31, 2013

	Year Ended December 31,
	2013			2012		2011
Current tax expense:
State income tax	$	1		$	2	$	2
Canadian federal and provincial income tax	99			51		36
Total current tax expense	$	100		$	53	$	38

Deferred tax (benefit)/expense:
State income tax	$	—		$	—	$	(2	)
Canadian federal and provincial income tax	(1		)	1		9
Total deferred tax (benefit)/expense	$	(1	)	$	1	$	7
Total income tax expense	$	99		$	54	$	45

Summary of differences between tax expense based on the statutory federal income tax rate and the entity's effective tax expense

	Year Ended December 31,
	2013			2012			2011
Income before tax	$	1,490		$	1,181		$	1,039
Partnership earnings not subject to current Canadian tax	(1,187		)	(1,046		)	(909		)
	$	303		$	135		$	130
Canadian federal and provincial corporate tax rate	25		%	25		%	27		%
Income tax at statutory rate	$	76		$	34		$	35

Canadian withholding taxes	$	19		$	18		$	12
Canadian permanent differences and rate changes	3			—			(2		)
State income tax	1			2			—
Total income tax expense	$	99		$	54		$	45

Deferred tax assets and liabilities

Deferred tax assets and liabilities are aggregated by the applicable tax paying entity and jurisdiction and presented net in “Other long-term liabilities and deferred credits” on our Consolidated Balance Sheet and result from the following (in millions):

	December 31,
	2013			2012
Deferred tax assets:
Book accruals in excess of current tax deductions	$	56		$	28
Total deferred tax assets	56			28

Deferred tax liabilities:
Property and equipment in excess of tax values	(398		)	(397		)
Total deferred tax liabilities	(398		)	(397		)
Net deferred tax liabilities	$	(342	)	$	(369	)