Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017
Defined Benefit Plan [Abstract]
Interest cost	$ (32)	$ (32)	$ (96)	$ (96)
Expected return on plan assets	41	52	123	156
Remeasurement gain, net	0	187	0	187
Net periodic pension benefits	$ 9	$ 207	$ 27	$ 247
Discount Rate				4.24%	3.68%