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Line of Credit Narrative (Details 2) - USD ($)
$ in Millions
Mar. 31, 2021
Dec. 31, 2020
Debt Disclosure [Abstract]    
Current borrowing capacity for line of credit facility $ 750  
Maximum borrowing capacity for line of credit facility 1,000  
Line of credit borrowings outstanding 0 $ 0
Outstanding letters of credit issued against line of credit facility $ 1 $ 1