v3.24.3
Fair Value Measurements (Tables)
 9 Months Ended
Sep. 30, 2024
Fair Value Disclosures [Abstract]  
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis
The following table presents the impact on the Consolidated Balance Sheets of MPLX’s financial instruments carried at fair value on a recurring basis as of September 30, 2024 and December 31, 2023 by fair value hierarchy level.
September 30, 2024December 31, 2023
(In millions)AssetLiabilityAssetLiability
Commodity contracts (Level 2)
Other current assets / Other current liabilities$1 $— $— $— 
Embedded derivatives in commodity contracts (Level 3)
Other current assets / Other current liabilities— 10 — 11 
Other noncurrent assets / Other long-term liabilities— 59 — 50 
Total carrying value in Consolidated Balance Sheets$1 $69 $— $61 
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation
The following table is a reconciliation of the net beginning and ending balances recorded for net liabilities classified as Level 3 in the fair value hierarchy.
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2024202320242023
Beginning balance $(69)$(53)$(61)$(61)
Unrealized and realized (loss)/gain included in Net Income(1)
(3)(10)(18)(7)
Settlements3 3 10 8 
Ending balance$(69)$(60)$(69)$(60)
The amount of total loss for the period included in earnings attributable to the change in unrealized (loss)/gain relating to liabilities still held at end of period$(3)$(9)$(15)$(6)
(1)    (Loss)/gain on derivatives embedded in commodity contracts are recorded in Purchased product costs in the Consolidated Statements of Income.
Fair Value Carrying Value by Balance Sheet Grouping The following table summarizes the fair value and carrying value of our third-party debt, excluding finance leases and unamortized debt issuance costs:
September 30, 2024December 31, 2023
(In millions)Fair ValueCarrying ValueFair ValueCarrying Value
Outstanding debt(1)
$21,494 $22,209 $19,377 $20,547 
(1)    Any amounts outstanding under the MPC Loan Agreement are not included in the table above, as the carrying value approximates fair value. This balance is reflected in Current liabilities - related parties in the Consolidated Balance Sheets.