New Accounting Pronouncements New Accounting Pronouncements - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 13, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other Non-current Assets	$ 365		$ 139
Reclassification of income	260	$ 6,136	7,828	$ 7,869
Reclassification of income	0	$ (26)	(46)	7
Operating Lease, Right-of-Use Asset						$ 256
Other Liabilities, Current	599		722
Other Non-current Liabilities	$ 554		$ 362
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other Non-current Assets							$ 288
Other Liabilities, Current							92
Other Non-current Liabilities							$ 219
Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of income				$ 41	$ 6