Pension Plans and Other Post Employment Benefit Plans Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets (Details) - Pension Plan - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accumulated benefit obligations	$ 20,654	$ 22,291	[1]
Fair value of plan assets	$ 16,620	17,934	[2]
Discontinued Operations [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accumulated benefit obligations		2,900
Fair value of plan assets		$ 2,000

[1] Includes $2.9 billion of discontinued operations for the period ended December 31, 2018.

[2] Includes $2.0 billion of discontinued operations for the period ended December 31, 2018.