Employee Benefits - Schedule of changes in level 3 fair value for Other Plans (Details) - Other - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Actual return on plan assets:
Balance at the beginning of the period	$ 1,019	$ 1,161
Foreign currency impact	(35)	(133)
Balance at the end of the period	1,076	1,019
Alternative investments
Actual return on plan assets:
Balance at the beginning of the period	9
Balance at the end of the period	9	9
Significant Unobservable Inputs (Level 3)
Actual return on plan assets:
Balance at the beginning of the period	0
Balance at the end of the period	0	0
Significant Unobservable Inputs (Level 3) | Alternative investments
Actual return on plan assets:
Balance at the beginning of the period	0
Balance at the end of the period	$ 0	$ 0