Benefits (Tables)

12 Months Ended

Dec. 31, 2014

General Discussion of Pension and Other Postretirement Benefits [Abstract]

Details about pension and OPEB plans

The following table presents details about our pension and OPEB plans:

	Pension						OPEB
	2014			2013			2014			2013
	(Millions of Dollars)
Change in Benefit Obligation
Benefit Obligation at January 1	$	1,410.2		$	1,508.5		$	362.7		$	381.2
Service cost	10.1			14.6			8.5			10.0
Interest cost	68.1			60.4			17.8			15.6
Participants' contributions	—			—			9.1			8.9
Plan amendments	—			(1.0		)	(4.6		)	—
Actuarial loss (gain)	120.4			(81.9		)	29.4			(27.7		)
Gross benefits paid	(103.3		)	(90.4		)	(26.4		)	(26.3		)
Federal subsidy on benefits paid	N/A			N/A			1.2			1.0
Benefit Obligation at December 31	$	1,505.5		$	1,410.2		$	397.7		$	362.7
Change in Plan Assets
Fair Value at January 1	$	1,451.0		$	1,385.4		$	327.6		$	285.4
Actual earnings on plan assets	88.5			147.3			17.7			45.5
Employer contributions	8.4			8.7			5.5			14.1
Participants' contributions	—			—			9.1			8.9
Gross benefits paid	(103.3		)	(90.4		)	(26.4		)	(26.3		)
Fair Value at December 31	$	1,444.6		$	1,451.0		$	333.5		$	327.6
Net liability (asset)	$	60.9		$	(40.8	)	$	64.2		$	35.1

Amounts recognized in Consolidated Balance Sheets

Amounts recognized in our Consolidated Balance Sheets as of December 31 related to the funded status of the benefit plans consisted of:

	Pension					OPEB
	2014		2013			2014		2013
	(Millions of Dollars)
Other long-term assets	$	39.2	$	138.7		$	39.5	$	40.2
Other long-term liabilities	100.1		97.9			103.7		75.3
Net liability (asset)	$	60.9	$	(40.8	)	$	64.2	$	35.1

Amounts not yet been recognized in net periodic benefit cost

The following table shows the amounts that have not yet been recognized in our net periodic benefit cost as of December 31 and are recorded as a regulatory asset on our balance sheet:

	Pension				OPEB
	2014		2013		2014			2013
	(Millions of Dollars)
Net actuarial loss	$	622.7	$	528.8	$	44.1		$	9.8
Prior service costs (credits)	6.8		8.8		(4.6		)	(1.7		)
Total - Regulatory Assets	$	629.5	$	537.6	$	39.5		$	8.1

Components of net periodic pension and OPEB costs

The components of net periodic pension and OPEB costs for the years ended December 31 are as follows:

	Pension									OPEB
	2014			2013			2012			2014			2013			2012
	(Millions of Dollars)
Net Periodic Benefit Cost
Service cost	$	10.1		$	14.6		$	21.7		$	8.5		$	10.0		$	10.3
Interest cost	68.1			60.4			65.5			17.8			15.6			20.3
Expected return on plan assets	(98.6		)	(95.8		)	(89.6		)	(23.7		)	(21.3		)	(19.0		)
Amortization of:
Transition obligation	—			—			—			—			—			0.3
Prior service cost (credit)	2.1			2.3			2.2			(1.8		)	(2.0		)	(1.9		)
Actuarial loss	36.7			54.5			41.0			1.2			3.7			7.3
Settlement charge	—			2.5			—			—			—			—
Other	—			—			0.4			—			—			—
Net Periodic Benefit Cost	$	18.4		$	38.5		$	41.2		$	2.0		$	6.0		$	17.3

	Pension			OPEB
	2014	2013	2012	2014	2013	2012
Weighted-Average assumptions used to
determine benefit obligations as of Dec. 31
Discount rate	4.15%	5.00%	4.10%	4.20%	4.95%	4.15%
Rate of compensation increase	4.0%	4.0%	4.0%	N/A	N/A	N/A
Weighted-Average assumptions used to
determine net cost for year ended Dec. 31
Discount rate	5.00%	4.10%	5.05%	4.95%	4.15%	5.20%
Expected return on plan assets	7.25%	7.25%	7.25%	7.50%	7.50%	7.50%
Rate of compensation increase	4.0%	4.0%	4.0%	N/A	N/A	N/A

Assumed health care cost trend rates as of Dec. 31	2014	2013	2012
Health care cost trend rate assumed for next year (Pre 65 / Post 65)	7.5%/7.5%	7.5%/7.5%	7.5%/7.5%
Rate that the cost trend rate gradually adjusts to	5.0%	5.0%	5.0%
Year that the rate reaches the rate it is assumed to remain at (Pre 65 / Post 65)	2021/2021	2021/2021	2017/2017

The expecte

A one-percentage-point change in assumed health care cost trend rates effects

A one-percentage-point change in assumed health care cost trend rates would have the following effects:

	1% Increase		1% Decrease
	(Millions of Dollars)
Effect on
Post-retirement benefit obligation	$	30.2	$	(25.4	)
Total of service and interest cost components	$	3.1	$	(2.5	)

Summary of fair value of plan assets by asset category within fair value hierarchy

The following table summarizes the fair value of our pension plan assets by asset category within the fair value hierarchy (for further level information, see Note M):

	As of December 31, 2014
Asset Category - Pension	Level 1		Level 2		Level 3		Total
	(Millions of Dollars)
Cash and Cash Equivalents	$	6.4	$	—	$	—	$	6.4
Equities:
U.S. Equity	503.8		—		—		503.8
International Equity	128.6		29.8		—		158.4
Fixed Income
Short, Intermediate and Long-term Bonds (a)
U.S. Bonds	42.5		599.3		—		641.8
International Bonds	79.3		43.3		—		122.6
Private Equity and Real Estate	—		—		11.6		11.6
Total	$	760.6	$	672.4	$	11.6	$	1,444.6

	As of December 31, 2013
Asset Category - Pension	Level 1		Level 2		Level 3		Total
	(Millions of Dollars)
Cash and Cash Equivalents	$	21.0	$	—	$	—	$	21.0
Equities:
U.S. Equity	519.5		—		—		519.5
International Equity	146.2		35.7		—		181.9
Fixed Income
Short, Intermediate and Long-term Bonds (a)
U.S. Bonds	108.4		505.2		—		613.6
International Bonds	78.1		36.9		—		115.0
Total	$	873.2	$	577.8	$	—	$	1,451.0

(a) This category represents investment grade bonds of U.S. and foreign issuers denominated in U.S. dollars from diverse industries.

The following table summarizes the fair value of our OPEB plan assets by asset category within the fair value hierarchy:

	As of December 31, 2014
Asset Category - OPEB	Level 1		Level 2		Level 3		Total
	(Millions of Dollars)
Cash and Cash Equivalents	$	1.4	$	—	$	—	$	1.4
Equities:
U.S. Equity	146.0		—		—		146.0
International Equity	42.2		2.5		—		44.7
Fixed Income:
Short, Intermediate and Long-term Bonds (a)
U.S. Bonds	3.5		112.4		—		115.9
International Bonds	17.5		7.0		—		24.5
Private Equity and Real Estate	—		—		1.0		1.0
Total	$	210.6	$	121.9	$	1.0	$	333.5

	As of December 31, 2013
Asset Category - OPEB	Level 1		Level 2		Level 3		Total
	(Millions of Dollars)
Cash and Cash Equivalents	$	2.6	$	—	$	—	$	2.6
Equities:
U.S. Equity	148.0		—		—		148.0
International Equity	46.9		2.8		—		49.7
Fixed Income:
Short, Intermediate and Long-term Bonds (a)
U.S. Bonds	8.4		96.3		—		104.7
International Bonds	16.8		5.8		—		22.6
Total	$	222.7	$	104.9	$	—	$	327.6

(a) This category represents investment grade bonds of U.S. and foreign issuers denominated in U.S. dollars from diverse industries.

Employer contributions to defined benefit plan

Cash Flows:

Historical employer contributions:

	Pension
Year	Qualified		Non-Qualified		OPEB
	(Millions of Dollars)
2012	$	95.6	$	7.1	$	17.7
2013	$	—	$	8.7	$	14.1
2014	$	—	$	8.4	$	5.5

Expected benefit payments in future

Estimated benefit payments:

Year	Pension		Gross OPEB
	(Millions of Dollars)
2015	$	104.7	$	25.5
2016	$	103.6	$	22.3
2017	$	104.3	$	22.8
2018	$	102.3	$	23.3
2019	$	102.4	$	24.1
2020-2024	$	491.8	$	122.5