Commitments and Contingencies - Concentrations of Credit Risk (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) Customer	Dec. 31, 2017 Customer	Jan. 29, 2019 USD ($)
Concentration Risk [Line Items]
Current accounts receivable	$ 2,747,911	$ 2,354,737
Customer Concentration Risk
Concentration Risk [Line Items]
Number of customers representing ten percent or more of revenue | Customer		0	0
Number of customers representing ten percent or more of net receivable position | Customer		0
PG&E
Concentration Risk [Line Items]
Receivables sold	36,000
Cash received from sale of receivables	34,000
PG&E | Pre-Petition Receivables
Concentration Risk [Line Items]
Accounts receivable	$ 7,000			$ 165,000
Current accounts receivable				$ 122,000