Long-Term Debt (Long-Term Debt) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt, beginning balance	$ 17,516
Principal Payments and Retirements	(5)
Long-term debt, ending balance	17,511
Long-term debt	17,511	$ 17,511	$ 17,516
Less: Debt Issuance Cost		(160)	(168)
Less: Debt Discount		(45)	(46)
Less: Current Portion		$ (17,306)	(994)
Total Long term debt			16,308
Interest rate		8.69%
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	5,711
Long-term debt, ending balance	5,706
Long-term debt	5,711	$ 5,706	5,711
Secured Debt [Member] | Parent Company [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	5,711
Principal Payments and Retirements	(5)
Long-term debt, ending balance	5,706
Long-term debt	5,706	$ 5,706	5,711
Interest rate		7.17%
Secured Debt [Member] | Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	106
Long-term debt, ending balance	106
Long-term debt	106	$ 106	106
Interest rate		8.37%
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	10,949
Long-term debt, ending balance	10,949
Long-term debt	10,949	$ 10,949	10,949
Unsecured Debt [Member] | Parent Company [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	10,949
Long-term debt, ending balance	10,949
Long-term debt	10,949	$ 10,949	10,949
Interest rate		9.62%
Unsecured Debt [Member] | Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	750
Long-term debt, ending balance	750
Long-term debt	$ 750	$ 750	$ 750
Interest rate		6.90%