Employee Benefit Plans - Schedule Fair Value of the Pension Assets (Details) - Pension Benefits - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets by asset category and by levels of fair value	$ 3,004	$ 1,866	$ 2,059
U.S. equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets by asset category and by levels of fair value	258	215
Global equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets by asset category and by levels of fair value	333	338
Fixed income and cash investment funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets by asset category and by levels of fair value	1,858	937
Other debt securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets by asset category and by levels of fair value	3	4
Private equities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets by asset category and by levels of fair value	51	60
Real estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets by asset category and by levels of fair value	84	35
Other investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets by asset category and by levels of fair value	$ 417	$ 277