XML 76 R64.htm IDEA: XBRL DOCUMENT v3.21.2
Fair Value Measurements - Changes in Fair Value of Financial Instruments Classified as Level 3 (Details) - Commodity Derivative Contracts Asset/(Liability) [Member]
$ in Millions
6 Months Ended
Jun. 30, 2021
USD ($)
Changes in fair value of financial instruments classified as Level 3 in fair value hierarchy [Roll Forward]  
Balance, beginning of period $ (0.2)
New Level 3 derivative instruments (0.2)
Transfers out of Level 3 0.2 [1]
Unrealized gain/(loss) included in OCI (1.3)
Balance, end of period $ (1.5)
[1] Transfers relate to long-term over-the-counter swaps for NGL products for which observable market prices became available for substantially their full term.