Revolving Credit Facilities	9 Months Ended
Sep. 30, 2018
Short-term Debt [Abstract]
Revolving Credit Facilities	Revolving Credit Facilities The Company has a $2.5 billion revolving credit facility that expires in July 2022. The Company had $0.5 billion in borrowings and no letters of credit outstanding under the credit facility as of September 30, 2018. The Company had $1.3 billion in borrowings and $159.4 million of letters of credit outstanding under the credit facility as of December 31, 2017. The maximum amount of outstanding borrowings at any time under the credit facility during the three and nine months ended September 30, 2018 was $0.7 billion and $1.6 billion, respectively, and the average daily balance of borrowings outstanding was approximately $0.3 billion and $0.9 billion, respectively, at a weighted average annual interest rate of approximately 3.6% and 3.3%, respectively. The Company had no borrowings or letters of credit outstanding under its credit facility at any time during the three and nine months ended September 30, 2017. EQM has a $1 billion revolving credit facility that expires in July 2022. EQM had $22 million in borrowings and $1 million of letters of credit outstanding under the credit facility as of September 30, 2018. EQM had $180 million in borrowings and no letters of credit outstanding under the credit facility as of December 31, 2017. The maximum amount of outstanding borrowings under EQM’s revolving credit facility at any time during the three and nine months ended September 30, 2018 was $74 million and $420 million, respectively, and the average daily balance of borrowings outstanding was approximately $22 million and $147 million, respectively. EQM incurred interest at a weighted average annual interest rate of approximately 3.7% and 3.2% for the three and nine months ended September 30, 2018, respectively. The maximum amount of outstanding borrowings under EQM's revolving credit facility at any time during each of the three and nine months ended September 30, 2017 was $177 million and the average daily balance of borrowings outstanding was approximately $95 million and $32 million, respectively. EQM incurred interest at a weighted average annual interest rate of approximately 2.7% for both the three and nine months ended September 30, 2017. Prior to the Separation, EQM intends to increase its borrowing capacity from $1 billion up to $3 billion. See Note B to the Condensed Consolidated Financial Statements for a discussion of the borrowings on the EQM Term Loan Facility. As a result of the termination of the EQM Term Loan Facility, EQM expensed $3 million of deferred issuance costs. From April 25, 2018 through June 25, 2018, the maximum amount of EQM's outstanding borrowings under the EQM Term Loan Facility at any time was $1,825 million and the average daily balance was approximately $1,231 million. EQM incurred interest at a weighted average annual interest rate of approximately 3.3% for the period from April 25, 2018 through June 25, 2018. In connection with the completion of the Midstream Mergers discussed in Note B, on July 23, 2018, EQM repaid the approximately $260 million of borrowings outstanding under the RMP Credit Agreement and the RMP Credit Agreement was terminated. RMP OpCo had $286 million in borrowings and $1 million of letters of credit outstanding under the RMP Credit Agreement as of December 31, 2017. The maximum amount of outstanding borrowings under the RMP Credit Agreement at any time from July 1, 2018 through July 23, 2018 and from January 1, 2018 through July 23, 2018 was $260 million and $375 million, respectively, and the average daily balance of borrowings outstanding during such periods was approximately $249 million and $300 million, respectively, at a weighted average annual interest rate of approximately 4.1% and 3.8%, respectively.

Revolving Credit Facilities

The Company has a $2.5 billion revolving credit facility that expires in July 2022. The Company had $0.5 billion in borrowings and no letters of credit outstanding under the credit facility as of September 30, 2018. The Company had $1.3 billion in borrowings and $159.4 million of letters of credit outstanding under the credit facility as of December 31, 2017. The maximum amount of outstanding borrowings at any time under the credit facility during the three and nine months ended September 30, 2018 was $0.7 billion and $1.6 billion, respectively, and the average daily balance of borrowings outstanding was approximately $0.3 billion and $0.9 billion, respectively, at a weighted average annual interest rate of approximately 3.6% and 3.3%, respectively. The Company had no borrowings or letters of credit outstanding under its credit facility at any time during the three and nine months ended September 30, 2017.

EQM has a $1 billion revolving credit facility that expires in July 2022. EQM had $22 million in borrowings and $1 million of letters of credit outstanding under the credit facility as of September 30, 2018. EQM had $180 million in borrowings and no letters of credit outstanding under the credit facility as of December 31, 2017. The maximum amount of outstanding borrowings under EQM’s revolving credit facility at any time during the three and nine months ended September 30, 2018 was $74 million and $420 million, respectively, and the average daily balance of borrowings outstanding was approximately $22 million and $147 million, respectively. EQM incurred interest at a weighted average annual interest rate of approximately 3.7% and 3.2% for the three and nine months ended September 30, 2018, respectively. The maximum amount of outstanding borrowings under EQM's revolving credit facility at any time during each of the three and nine months ended September 30, 2017 was $177 million and the average daily balance of borrowings outstanding was approximately $95 million and $32 million, respectively. EQM incurred interest at a weighted average annual interest rate of approximately 2.7% for both the three and nine months ended September 30, 2017. Prior to the Separation, EQM intends to increase its borrowing capacity from $1 billion up to $3 billion.

See Note B to the Condensed Consolidated Financial Statements for a discussion of the borrowings on the EQM Term Loan Facility. As a result of the termination of the EQM Term Loan Facility, EQM expensed $3 million of deferred issuance costs. From April 25, 2018 through June 25, 2018, the maximum amount of EQM's outstanding borrowings under the EQM Term Loan Facility at any time was $1,825 million and the average daily balance was approximately $1,231 million. EQM incurred interest at a weighted average annual interest rate of approximately 3.3% for the period from April 25, 2018 through June 25, 2018.

In connection with the completion of the Midstream Mergers discussed in Note B, on July 23, 2018, EQM repaid the approximately $260 million of borrowings outstanding under the RMP Credit Agreement and the RMP Credit Agreement was terminated. RMP OpCo had $286 million in borrowings and $1 million of letters of credit outstanding under the RMP Credit Agreement as of December 31, 2017. The maximum amount of outstanding borrowings under the RMP Credit Agreement at any time from July 1, 2018 through July 23, 2018 and from January 1, 2018 through July 23, 2018 was $260 million and $375 million, respectively, and the average daily balance of borrowings outstanding during such periods was approximately $249 million and $300 million, respectively, at a weighted average annual interest rate of approximately 4.1% and 3.8%, respectively.