Benefit Plans, Amounts Recognized in the Consolidated Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits [Member]
Amounts recognized in the Consolidated Balance Sheets consist of [Abstract]
Other assets	$ 4	$ 5
Other liabilities	(508)	(566)
Net amount recognized	(504)	(561)
Other Postretirement Benefits [Member]
Amounts recognized in the Consolidated Balance Sheets consist of [Abstract]
Other assets	61	54
Other liabilities	(16)	(16)
Net amount recognized	$ 45	$ 38