XML 60 R49.htm IDEA: XBRL DOCUMENT v3.20.2
Summary of Significant Accounting Policies - Pension Plan Contributions (Details) - Pension Plan - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2020
Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]    
Anticipated employer contribution   $ 56
Cash contributions $ 12