Income Taxes 3 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance, January 1	$ 73	$ 24	$ 308
Increases:
Current year tax positions	5	4	8
Tax positions related to prior years	4	46	0
Decreases:
Tax positions related to prior years	0	0	(289)
Lapse of statute of limitations	(2)	(1)	(3)
Balance, December 31	$ 80	$ 73	$ 24