Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Income tax (Details)

v3.21.2
Summary of Significant Accounting Policies - Income tax (Details) - Adjustment Effect - West Virginia
$ in Millions
Sep. 30, 2021
USD ($)
Income taxes  
Deferred tax liabilities $ (34)
Deferred tax assets 48
Valuation allowance $ 14