Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Earliest Open Tax Years Subject to Examination by State Taxing Authorities in the Major Operating Jurisdictions

State Audits—Xcel Energy files consolidated state tax returns based on income in its major operating jurisdictions of Colorado, Minnesota, Texas, and Wisconsin, and various other state income-based tax returns. As of Dec. 31, 2015, Xcel Energy’s earliest open tax years that are subject to examination by state taxing authorities in its major operating jurisdictions were as follows:

State	Year
Colorado	2009
Minnesota	2009
Texas	2009
Wisconsin	2011

Reconciliation of Unrecognized Tax Benefits

A reconciliation of the amount of unrecognized tax benefit is as follows:

(Millions of Dollars)	Dec. 31, 2015		Dec. 31, 2014
Unrecognized tax benefit — Permanent tax positions	$	25.8	$	16.2
Unrecognized tax benefit — Temporary tax positions	94.9		50.3
Total unrecognized tax benefit	$	120.7	$	66.5

A reconciliation of the beginning and ending amount of unrecognized tax benefit is as follows:

(Millions of Dollars)	2015			2014			2013
Balance at Jan. 1	$	66.5		$	41.2		$	34.5
Additions based on tax positions related to the current year	27.1			28.7			15.1
Reductions based on tax positions related to the current year	(4.5		)	(2.0		)	(0.4		)
Additions for tax positions of prior years	34.8			16.0			21.6
Reductions for tax positions of prior years	(2.9		)	(6.0		)	(4.8		)
Settlements with taxing authorities	(0.3		)	(9.6		)	(24.8		)
Lapse of applicable statutes of limitations	—			(1.8		)	—
Balance at Dec. 31	$	120.7		$	66.5		$	41.2

Tax Benefits Associated with NOL and Tax Credit Carryforwards

The unrecognized tax benefit amounts were reduced by the tax benefits associated with NOL and tax credit carryforwards. The amounts of tax benefits associated with NOL and tax credit carryforwards are as follows:

(Millions of Dollars)	Dec. 31, 2015			Dec. 31, 2014
NOL and tax credit carryforwards	$	(36.7	)	$	(28.5	)

NOL and Tax Credit Carryforwards

Other Income Tax Matters — NOL amounts represent the amount of the tax loss that is carried forward and tax credits represent the deferred tax asset. NOL and tax credit carryforwards as of Dec. 31 were as follows:

(Millions of Dollars)	2015			2014
Federal NOL carryforward	$	2,153		$	1,349
Federal tax credit carryforwards	360			327
State NOL carryforwards	2,124			1,722
Valuation allowances for state NOL carryforwards	(65		)	(53		)
State tax credit carryforwards, net of federal detriment (a)	45			19
Valuation allowances for state credit carryforwards, net of federal benefit (b)	(24		)	—

^(a)  State tax credit carryforwards are net of federal detriment of $24 million and $10 million as of Dec. 31, 2015 and 2014, respectively.

^(b)  Valuation allowances for state tax credit carryforwards were net of federal benefit of $13 million as of Dec. 31, 2015.

Schedule of Effective Income Tax Rate Reconciliation

Total income tax expense from operations differs from the amount computed by applying the statutory federal income tax rate to income before income tax expense. The following reconciles such differences for the years ending Dec. 31:

	2015		2014		2013
Federal statutory rate	35.0	%	35.0	%	35.0	%
Increases (decreases) in tax from:
State income taxes, net of federal income tax benefit	4.1		4.0		4.1
Change in unrecognized tax benefits	0.6		0.2		0.6
NOL carryback	(0.3	)	(0.9	)	(0.8	)
Regulatory differences — utility plant items	(1.0	)	(1.3	)	(1.6	)
Tax credits recognized, net of federal income tax expense	(2.7	)	(2.6	)	(2.6	)
Other, net	(0.2	)	(0.5	)	(0.9	)
Effective income tax rate	35.5	%	33.9	%	33.8	%

Schedule of Components of Income Tax Expense (Benefit)

The components of Xcel Energy’s income tax expense for the years ending Dec. 31 were:

(Thousands of Dollars)	2015			2014			2013
Current federal tax (benefit)	$	(36,129	)	$	(73,160	)	$	(46,173	)
Current state tax expense	2,324			9,225			7,678
Current change in unrecognized tax expense	45,933			23,915			13,162
Deferred federal tax expense	480,078			505,236			439,085
Deferred state tax expense	92,132			84,787			80,907
Deferred change in unrecognized tax (benefit)	(36,342		)	(20,645		)	(4,930		)
Deferred investment tax credits	(5,277		)	(5,543		)	(5,753		)
Total income tax expense	$	542,719		$	523,815		$	483,976

The components of deferred income tax expense for the years ending Dec. 31 were:

(Thousands of Dollars)	2015			2014			2013
Deferred tax expense excluding items below	$	546,664		$	616,934		$	588,053
Amortization and adjustments to deferred income taxes on income tax regulatory assets and liabilities	(11,810		)	(48,674		)	(64,420		)
Tax benefit (expense) allocated to OCI	1,013			1,117			(8,572		)
Other	1			1			1
Deferred tax expense	$	535,868		$	569,378		$	515,062

Schedule of Deferred Tax Assets and Liabilities

The components of Xcel Energy’s net deferred tax liability (current and noncurrent) at Dec. 31 were as follows:

(Thousands of Dollars)	2015			2014
Deferred tax liabilities:
Differences between book and tax bases of property	$	7,119,023		$	6,257,191
Regulatory assets	313,414			300,762
Other	243,690			300,251
Total deferred tax liabilities	$	7,676,127		$	6,858,204
Deferred tax assets:
NOL carryforward	$	851,242		$	552,274
Tax credit carryforward	404,738			346,064
Unbilled revenue - fuel costs	57,220			55,021
Rate refund	50,441			93,956
Regulatory liabilities	41,541			49,712
Environmental remediation	38,663			42,716
Deferred investment tax credits	29,650			31,886
NOL and tax credit valuation allowances	(27,679		)	(3,402		)
Other	76,869			83,199
Total deferred tax assets	$	1,522,685		$	1,251,426
Net deferred tax liability	$	6,153,442		$	5,606,778