Postretirement Benefit Plans (Components of Pension Plans) (Details) - USD ($) $ in Millions		12 Months Ended
	Jul. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss		$ 83	$ 37	$ 19
Prior service cost		0	0	1
Settlement		(9)	(1)	(1)
Total recognized in comprehensive income		0	0	(6)
Defined benefit pension plans
Net periodic benefit cost:
Net periodic benefit cost		19	5	12
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Change recognized in other comprehensive income		69	12	33
Total recognized in comprehensive income		88	17	45
United States
Net periodic benefit cost:
Service cost		3	3	3
Interest cost		4	4	4
Expected return on plan assets		(8)	(7)	(6)
Amortization of net actuarial loss		1	2	2
Net periodic benefit cost		0	2	3
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss		6	1	1
Prior service cost		0	0	(1)
Amortization of net actuarial loss		(1)	(2)	(2)
Change recognized in other comprehensive income		5	(1)	0
International defined benefit pension plans
Net periodic benefit cost:
Service cost		9	9	12
Interest cost		19	19	21
Expected return on plan assets		(27)	(35)	(34)
Amortization of net actuarial loss		9	9	9
Settlement		9	1	1
Net periodic benefit cost		19	3	9
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss		79	35	23
Prior service cost		0	(3)	(1)
Amortization of net actuarial loss		(9)	(9)	(9)
Settlement		(9)	(1)	(1)
Foreign Exchange		3	(15)	19
Change recognized in other comprehensive income		$ 64	$ 13	$ 33
International defined benefit pension plans | Defined benefit pension plans
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss	$ 11