Share-Based Compensation Plans - Schedule of Share-Based Compensation Expense (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 38,143,000	$ 24,904,000	$ 112,766,000
Less: Discontinued operations	0	(18,250,000)	(15,595,000)
Cash received from exercises of all share-based payment arrangements for employees and directors	0	1,900,000	200,000
Income tax benefit by the exercise of nonqualified employee stock options and vesting of restricted share awards	4,900,000	13,400,000	58,900,000
Proxy, Transaction, and Reorganization Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	28,600,000
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	14,430,000	14,503,000	87,104,000
Non-qualified stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	4,774,000	2,757,000	2,626,000
Other programs, including non-employee director awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	2,257,000	3,014,000	1,005,000
2015 Executive Performance Incentive Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	0	0	5,348,000
2016 Incentive Performance Share Unit Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	0	6,863,000	13,077,000
2017 Incentive Performance Share Unit Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	(681,000)	2,467,000	5,038,000
2018 Incentive Performance Share Unit Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	(952,000)	4,742,000	0
2019 Incentive Performance Share Unit Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	14,939,000	0	0
2016 EQT Value Driver Performance Share Unit Award Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	0	0	3,341,000
2017 EQT Value Driver Performance Share Unit Award Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	0	584,000	10,822,000
2018 EQT Value Driver Performance Share Unit Award Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	(248,000)	8,224,000	0
2019 EQT Value Driver Performance Share Unit Award Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 3,624,000	$ 0	$ 0

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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