Quarterly Results (Unaudited) (Details Textual) - USD ($) $ in Millions	3 Months Ended							12 Months Ended
	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Asset Impairment, Total			$ 51	$ 6				$ 51	$ 6	$ 20
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	$ (14)	$ 56	$ (34)		$ (22)	$ (87)	$ (16)	6	(2)	1
Write off of Deferred Debt Issuance Cost	3	$ 5						8	2
Equity Securities, FV-NI, Unrealized Gain (Loss), Total	$ 33
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement						$ (258)			(259)
Gain (Loss) on Extinguishment of Debt, Total				$ (9)				$ (8)	$ (9)