Equity-Based Compensation Plan (Tables)

9 Months Ended

Sep. 30, 2020

Phantom Units

Equity Transactions And Share Based Compensation [Line Items]

Summary of Share-based Compensation, Restricted Stock Units Award Activity

The following is a summary of phantom unit award activity of MPLX LP common units for the nine months ended September 30, 2020:

	Number of Units		Weighted Average Fair Value
Outstanding at December 31, 2019	1,109,568		$	35.97
Granted	215,677		19.31
Settled	(558,398	)	37.73
Forfeited	(5,383	)	35.87
Outstanding at September 30, 2020	761,464		$	29.96

Performance Shares [Member]

Equity Transactions And Share Based Compensation [Line Items]

Summary of Share-based Compensation, Restricted Stock Units Award Activity

Performance Units – MPLX grants performance units to certain officers of the general partner and certain eligible MPC officers who make significant contributions to its business. These performance units pay out 75 percent in cash and 25 percent in MPLX LP common units and often contain both market and performance conditions based on various metrics. Market conditions are valued using a Monte Carlo valuation while performance conditions are reevaluated periodically and valued at the compensation cost associated with the performance outcome deemed most probable.

The performance units granted in 2020 are hybrid awards having a three-year performance period of January 1, 2020 through December 31, 2022. The payout of the award is dependent on two independent conditions, each constituting 50 percent of the overall target units granted. The awards have a performance condition based on MPLX LP’s distributable cash flow, and a market condition based on MPLX LP’s total unitholder return. The market condition was valued using a Monte Carlo valuation, resulting in a grant date fair value of $0.80 per unit for the 2020 equity-classified performance units. Grant date fair value of the performance condition is based on potential payouts per unit of up to $2.00 per unit. Compensation cost associated with the performance condition is based on the grant date fair value of the payout deemed most probable to occur and is adjusted as the expectation for payout changes.

During the first quarter of 2018, a performance award was granted; however, due to the nature of the award terms, the grant date for this award was not established until the first quarter of 2020 and we began recognizing units and expense related to this award at that time. The performance units granted in 2018 are hybrid awards having a three-year performance period of January 1, 2018 through December 31, 2020. The payout of the award is dependent on two independent conditions, each constituting 50 percent of the overall target units granted. The awards have a performance condition based on an average of MPLX LP’s distributable cash flow and a market condition based on MPLX LP’s total unitholder return. The market condition was valued using a Monte Carlo valuation, resulting in a grant date fair value of $0.45 per unit for the 2018 equity-classified performance units. Grant date fair value of the performance condition is based on potential payouts per unit of up to $2.00 per unit. Compensation cost associated with the performance condition is based on the grant date fair value of the payout deemed most probable to occur and is adjusted as the expectation for payout changes.

The following is a summary of the activity for performance unit awards to be settled in MPLX LP common units for the nine months ended September 30, 2020:

	Number of Units
Outstanding at December 31, 2019	2,157,347
Granted	2,147,211
Settled	(1,169,354	)
Forfeited	(31,668	)
Outstanding at September 30, 2020	3,103,536