Employee Retirement Plans

We maintain defined benefit pension plans for most of our employees. Most of these plans require employee contributions in order to accrue benefits. Benefits payable under the plans are based on employees’ years of service and compensation during specified years of employment. Effective December 31, 2010, we amended the USG Corporation defined benefit pension plan to replace the final average pay formula with a cash balance formula for employees hired after that date.

In 2013, we communicated to certain terminated vested participants in our USG Corporation Retirement Plan an option to receive a lump sum payment for their accrued benefits. The option commenced on October 1, 2013 and expired on November 15, 2013. For participants who elected this option, payments were made in December 2013, and we incurred a settlement charge of approximately $15 million, with a corresponding reduction in accumulated other comprehensive income (loss).

We had maintained a pension plan for our subsidiary USG (U.K.) Ltd which had been previously frozen to permanently eliminate future benefit accruals. In December 2014, we irrevocably purchased annuities for the remaining deferred members of the plan relieving us of the responsibility of the pension benefit obligation, or PBO. Consequently, we recorded a settlement charge in selling and administrative expenses in the amount of $13 million and removed the net pension asset from our consolidated balance sheet.

We also maintain plans that provide postretirement benefits (retiree health care and life insurance) for eligible employees. Employees hired before January 1, 2002 generally become eligible for the postretirement benefit plans when they meet minimum retirement age and service requirements. The cost of providing most postretirement benefits is shared with retirees.

In 2011 and 2014, we amended our U.S. postretirement benefit plan to require retiree medical plan participants to begin purchasing individual coverage in the Affordable Insurance Exchanges or individual Medicare marketplace beginning January 1, 2016 using a company-funded subsidy. The subsidy will be determined based upon years of service at retirement and Medicare eligibility. The subsidy provided to retirees eligible for Medicare will end December 31, 2019. As a result of the amendments, the measurement of the accumulated postretirement benefit obligation, or APBO, was reduced and a credit to unrecognized prior service cost is being amortized into the statement of operations over the average remaining service of active plan participants to retirement eligibility.

The components of net pension and postretirement benefit costs are summarized in the following table:



(millions)	2015			2014			2013
Pension Benefits:
Service cost of benefits earned	$	49		$	37		$	38
Interest cost on projected benefit obligation	66			65			63
Expected return on plan assets	(83		)	(79		)	(76		)
Settlement ^(a)	1			13			16
Net amortization	39			24			43
Net pension cost	$	72		$	60		$	84
Postretirement Benefits:
Service cost of benefits earned	$	2		$	3		$	3
Interest cost on projected benefit obligation	6			7			7
Net amortization	(31		)	(35		)	(34		)
Net postretirement benefit	$	(23	)	$	(25	)	$	(24	)


(a)	In 2014, the settlement charge related to the elimination of the benefit obligation of the UK pension plan due to the purchase of annuities. In 2013, the settlement charge primarily related to lump sum payments made to certain terminated vested participants in our U.S. Plan.

We use a December 31 measurement date for our plans. The accumulated benefit obligation, or ABO, for the defined benefit pension plans was $1.354 billion as of December 31, 2015 and $1.429 billion as of December 31, 2014.



	As of December 31,
(millions)	2015			2014
Selected information for pension plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	$	(1,182	)	$	(1,230	)
Fair value of plan assets	1,097			1,113
Selected information for pension plans with benefit obligations in excess of plan assets:
Benefit obligation	$	(1,365	)	$	(1,686	)
Fair value of plan assets	1,099			1,340

The following table summarizes projected benefit obligations, plan assets and funded status as of December 31:



	Pension						Postretirement
(millions)	2015			2014			2015			2014
Change in Benefit Obligation:
Benefit obligation as of January 1	$	1,686		$	1,376		$	167		$	166
Service cost	49			37			2			3
Interest cost	66			65			6			7
Curtailment/settlements	(4		)	(24		)	—			—
Participant contributions	11			10			3			8
Benefits paid	(86		)	(81		)	(11		)	(20		)
Plan amendment	—			—			—			4
Actuarial (gain) loss	(119		)	327			(14		)	4
Foreign currency translation	(39		)	(24		)	(9		)	(5		)
Benefit obligation as of December 31	$	1,564		$	1,686		$	144		$	167
Change in Plan Assets:
Fair value as of January 1	$	1,340		$	1,262		$	—		$	—
Actual return on plan assets	17			132			—			—
Employer contributions	61			64			8			12
Participant contributions	11			10			3			8
Benefits paid	(86		)	(81		)	(11		)	(20		)
Curtailment/settlements	(4		)	(24		)	—			—
Foreign currency translation	(38		)	(23		)	—			—
Fair value as of December 31	$	1,301		$	1,340		$	—		$	—
Funded status	$	(263	)	$	(346	)	$	(144	)	$	(167	)
Components on the Consolidated Balance Sheets:
Noncurrent assets	$	3		$	—		$	—		$	—
Current liabilities	(9		)	(9		)	(9		)	(13		)
Noncurrent liabilities	(257		)	(337		)	(135		)	(154		)
Net liability as of December 31	$	(263	)	$	(346	)	$	(144	)	$	(167	)
Pretax Components in AOCI:
Net actuarial loss	$	387		$	490		$	7		$	24
Prior service credit	(1		)	(1		)	(108		)	(140		)
Total as of December 31	$	386		$	489		$	(101	)	$	(116	)

For our defined benefit pension plans, the 2015 actuarial gain of $119 million was primarily due to an increase in the discount rates and the adoption of the new mortality tables published by the Society of Actuaries used to determine the benefit obligation. The weighted-average discount rate increased from 4.10% at December 31, 2014 to 4.43% at December 31, 2015 and decreased from 4.90% at December 31, 2013 to 4.10% at December 31, 2014.

For the defined benefit pension plans, we estimate that during 2016 we will amortize from AOCI into net pension cost a net actuarial loss of $19 million and no prior service cost. For the postretirement benefit plans, we estimate that during 2016 we will amortize from AOCI into net postretirement cost a net actuarial loss of $1 million and a prior service credit of $28 million.

ASSUMPTIONS

The following tables reflect the assumptions used in the accounting for our plans:



	Pension				Postretirement
	2015		2014		2015		2014
Weighted average assumptions used to determine benefit obligations as of December 31:
Discount rate	4.43	%	4.10	%	4.24	%	3.70	%
Compensation increase rate	3.55	%	3.60	%	N/A		N/A
Weighted average assumptions used to determine net cost for years ended December 31:
Discount rate	4.10	%	4.90	%	3.70	%	4.60	%
Expected return on plan assets	6.70	%	7.00	%	N/A		N/A
Compensation increase rate	3.50	%	3.50	%	N/A		N/A

We no longer have significant exposure to health care cost trend rates due to the modifications we made to our U.S. postretirement health care plan to limit the increase in the annual amount we pay for retiree health care coverage for certain current and future retirees to 3% and to require retiree medical plan participants to begin purchasing individual coverage in the Affordable Insurance Exchanges or individual Medicare marketplace beginning January 1, 2016 using a company-funded subsidy based upon years of service at retirement.

For the measurement of the APBO at December 31, 2015 for our Canadian postretirement health care plan, the assumed health care cost trend rates start with an 8% increase in 2016, followed by a gradual decline in increases to 4% for 2032. For the measurement of the APBO at December 31, 2014, the assumed health care cost trend rates started with a 8.25% increase in 2015, followed by a gradual decline in increases to 4% for 2032 and beyond.

A one percentage point change in the assumed health care cost trend rates would have the following effects on our U.S. and Canadian plans:



(millions)	One-Percentage- Point Increase		One-Percentage- Point Decrease
Effect on total service and interest cost	$	1	$	—
Effect on postretirement benefit obligation	10		(8		)

RETIREMENT PLAN ASSETS

Investment Policies and Strategies: We have established investment policies and strategies for the defined benefit pension plans’ assets with a long-term objective of maintaining the plans’ assets at a level equal to or greater than that of their liabilities (as measured by a funded ratio of 100% or more of the ABO) and maximizing returns on the plans’ assets consistent with our moderate tolerance for risk. Contributions are made to the plans periodically as needed to meet funding targets or requirements. Factors influencing our determination to accept a moderate degree of risk include the timing of plan participants’ retirements and the resulting disbursement of retirement benefits, the liquidity requirements of the plans and our financial condition.

Our overall long-term objective is to achieve a 6.7% rate of return on plan assets with a moderate level of risk as indicated by the volatility of investment returns. This rate of return target was established using a “building block” approach. In this approach, ranges of long-term expected returns for the various asset classes in which the plans invest are estimated. The estimated ranges are primarily based on observations of historical asset returns and their historical volatility. In determining the expected returns, we also consider consensus forecasts of certain market and economic factors that influence returns, such as inflation, gross domestic product trends and dividend yields. We then calculate an overall range of likely expected rates of return by applying the expected asset returns to the plans’ target asset allocation. The most likely rate of return is then determined and is adjusted to account for investment management fees.

Our investment strategy is to invest in a diversified mix of asset classes in accordance with an asset allocation that we believe is likely to achieve our long-term target return while prudently considering risk. In order to manage risk, the plans’ pension and investment committees periodically rebalance the asset allocations as outlined by our investment policy statements. Our investment policy statements include glide paths which outline how our asset allocation would increase the portion of liability-hedging assets, such as fixed income, as our funded status improves in the future. This liability-driven investing approach is carried out by professional investment managers who help the committees in this process. The committees also monitor the investment performance of the individual investment managers compared to their benchmark returns and investment guidelines on an ongoing basis, in part through the use of quarterly investment portfolio reviews and compliance reporting by investment managers. The pension and investment committees also evaluate risk by periodically conducting asset/liability studies to assess the correlation of the plans’ assets and liabilities and the degree of risk in the target asset allocations. The plans limit the use of leverage to select investment strategies where leverage is typically employed, such as private equity and real estate. Certain investment managers utilize derivatives, such as swaps, bond futures, and options, as part of their investment strategies. This is done primarily to gain a desired market exposure or manage factors such as interest rate risk or duration of a bond portfolio.

The following table shows the aggregate target asset allocation on a weighted average basis for all the plans and the acceptable ranges around the targets as of December 31, 2015.



		Investment Policy
		Target		Range
Asset Categories:	Asset Category Description
Equity	Institutional commingled/pooled equity funds, equity mutual funds and direct holdings of the common stock of U.S. and non-U.S. companies; equity funds and direct holdings are invested in companies with a range of market capitalizations	40	%	36% - 42%
Fixed income	U.S. Treasury securities, non-U.S. government debt securities such as Canadian federal bonds, corporate bonds of companies from diversified industries and mortgage-backed securities	49	%	46% - 52%
Limited partnerships	Investments in funds that follow any of several different strategies, including investing in distressed debt, energy development, infrastructure, and hedge funds. These investments use strategies with returns normally expected to have a reduced correlation to the return of equities as compared to other asset classes and often provide a current income component that is a meaningful portion of the investment’s total return.	5	%	2% -8%
Other real assets	Primarily investments in large core, private real estate funds that directly own a diverse portfolio of properties located in the United States. It also includes an allocation to funds investing in equities of real estate and infrastructure companies	6	%	3% - 9%
Cash equivalents and short-term investments	Primarily held in short-term investment funds or registered money market funds with daily liquidity	—	%	0% - 5%
Total		100	%

Fair Values of Plan Assets: Pension assets are classified based on the valuation methodologies and inputs used to determine the fair value as described in Note 1.

Level 1 investments include mutual funds, or direct investments in common stocks of U.S. and non-U.S. companies that trade on liquid exchanges. These investments are valued based on the closing price on these exchanges.

Level 2 investments include primarily fixed income securities such as corporate, or government debentures, mortgage- and asset-backed securities. They are valued primarily using income and market approaches, such as pricing based on recent market transactions, and values are based on quoted prices or other observable market inputs received from data providers. Commingled funds not traded on an exchange, even though their underlying investments are common stocks traded on liquid exchanges, are also included in the Level 2 category. The net asset value of commingled funds investing in either stocks or fixed income securities is calculated by subtracting the value of any liabilities from the market value of all securities owned by a fund.

Level 3 investments include real estate, infrastructure, or direct energy investments as well as distressed securities or hedge funds. These are valued using income approach methodologies such as discounted cash flows, or market approach methodologies such as relative value (specific to equity securities), direct capitalization and comparable sales (specific to real estate investments). Some of the key inputs used to value these securities include discount rate, EBITDA multiple, yield-to-worst, yield-to-maturity, and cap rate (specific to real estate investments).

The fair values by hierarchy of inputs as of December 31 were as follows:



	Quoted Prices in Active Markets for Identical Assets (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Unobservable Inputs (Level 3)				Total
(millions)	2015		2014		2015		2014		2015		2014		2015			2014
Asset Categories:
Equity: (a)
Common and preferred stock	$	55	$	74	$	—	$	—	$	—	$	—	$	55		$	74
Commingled/pooled/mutual funds	54		53		448		470		—		—		502			523
Total equity	109		127		448		470		—		—		557			597
Fixed income:
U.S. government and agency debt securities	—		—		177		195		—		—		177			195
Non-U.S. government and agency debt securities	—		—		32		30		—		—		32			30
Investment-grade debt securities	—		—		199		184		—		—		199			184
High-yield debt securities	—		—		36		39		—		—		36			39
Commingled/pooled funds	—		—		129		114		—		—		129			114
Other	—		—		3		8		1		1		4			9
Total fixed income	—		—		576		570		1		1		577			571
Limited partnerships	—		—		—		—		106		103		106			103
Other real estate assets	—		—		15		20		37		35		52			55
Cash equivalents and short-term investments	—		—		10		17		—		—		10			17
Total	$	109	$	127	$	1,049	$	1,077	$	144	$	139	$	1,302		$	1,343
Cash on hand													—			—
Receivables													9			1
Accounts payable													(10		)	(4		)
Total													$	1,301		$	1,340


(a)	Certain investments in commingled/pooled equity funds have been classified as Level 2 in 2015 and 2014 because observable quoted prices for these institutional funds are not available.

A reconciliation of the change in the fair value measurement of the defined benefit plans’ consolidated assets using significant unobservable inputs (Level 3) between January 1, 2014 and December 31, 2015 is as follows:



(millions)	Fixed Income		Other Real Estate Assets			Limited Partnerships			Total
Balance as of January 1, 2014	$	1	$	35		$	39		$	75
Realized gains	—		1			—			1
Unrealized gains (losses)	—		1			(2		)	(1		)
Purchases, sales and settlements:
Purchases	—		—			67			67
Sales	—		(2		)	(1		)	(3		)
Settlements	—		—			—			—
Net transfers into (out of) Level 3	—		—			—			—
Balance as of December 31, 2014	$	1	$	35		$	103		$	139
Realized losses	—		(1		)	—			(1		)
Unrealized gains	—		5			1			6
Purchases, sales and settlements:
Purchases	—		—			2			2
Sales	—		(2		)	—			(2		)
Settlements	—		—			—			—
Net transfers into (out of) Level 3	—		—			—			—
Balance as of December 31, 2015	$	1	$	37		$	106		$	144

CASH FLOWS

For 2016, our defined benefit pension plans have no minimum funding requirements under the Employee Retirement Income Security Act of 1974. We are evaluating our level of funding for pension plans and currently estimate that we will contribute approximately $65 million to our pension plans in 2016. Our cash payments for postretirement plans are estimated to be $9 million in 2016.

Total benefit payments we expect to make to participants, which include payments funded from USG’s assets as well as payments from our pension plans' assets, are as follows (in millions):



Years ended December 31	Pension Benefits		Postretirement Benefits
2016	$	105	$	9
2017	84		9
2018	94		10
2019	95		10
2020	128		8
2021 - 2025	585		43

DEFINED CONTRIBUTION PLANS

Total charges for our defined contribution plans amounted to approximately $7 million, $6 million and $3 million for the years ended December 31, 2015, 2014 and 2013, respectively. These charges primarily consisted of contributions to our U.S. plan, commonly known as a 401(k) plan. The U.S. plan provides participating employees the opportunity to invest 1% to 75% of their compensation on a pretax and/or Roth after-tax basis. Effective January 1, 2014, participants earn a guaranteed company match of 25% on employee contributions up to 6% of their eligible compensation. During 2013 the company match was 10% on contributions up to 6% of their eligible compensation. Employees are fully vested in company matching contributions after three years of participation in the plan. USG’s contributions are charged to cost of products sold and selling and administrative expenses.