Quarterly Financial Data (Unaudited) Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended								11 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 13, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Other Nonrecurring (Income) Expense		$ 342	$ 487	$ 125	$ 298	$ 2,000	$ 95	$ 109	$ 57
Goodwill, Impairment Loss	$ 0		(399)	(102)	(229)	$ (1,900)				$ (730)		$ (1,917)	$ 0
Reorganization Items	4	$ 5,700	$ 303							(5,389)		0	0
Prepetition Charges	0			(76)						(86)	$ (86)	0	0
Restructuring Charges	0			(61)						(189)		(126)	(183)
Gain (Loss) on Disposition of Business	0			$ 114						(112)		0	96
Asset Write Down and Other	$ 0				$ 69					$ 374		$ 238	$ 1,701