Employee Benefit Plans (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Components of Net Periodic Benefit Costs:
Defined benefit plans	$ 24,000,000	$ 36,000,000
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive (Loss) Income:
Net actuarial loss	12,000,000	15,000,000
Amortization of net actuarial (loss) gain	(40,000,000)	(45,000,000)
Amortization of net prior service credit	19,000,000	19,000,000
Pension Plan
Contributions [Abstract]
Defined benefit plan, contributions by employer	33,000,000	34,000,000	$ 141,000,000
Defined benefit plan, expected future employer contributions	135,000,000
Pension Plan | U.S.
Components of Net Periodic Benefit Costs:
Service cost	1,000,000	0
Interest cost	23,000,000	30,000,000
Expected return on plan assets	(26,000,000)	(26,000,000)
Recognized net actuarial loss (gain)	7,000,000	5,000,000
Amortization of prior service credit	0	0
Recognized settlement loss	19,000,000	31,000,000
Recognized curtailment gain	0	0
Defined benefit plans	24,000,000	40,000,000
Defined contribution plans	5,000,000	8,000,000
Net Periodic Benefit Cost (Credit)	29,000,000	48,000,000
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive (Loss) Income:
Net actuarial loss	12,000,000	15,000,000
Amortization of net actuarial (loss) gain	(26,000,000)	(36,000,000)
Amortization of net prior service credit	0	0
Total Recognized in Other Comprehensive (Loss) Income	(14,000,000)	(21,000,000)
Total Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Loss) Income	15,000,000	27,000,000
Contributions [Abstract]
Defined benefit plan, contributions by employer	6,000,000	6,000,000	26,000,000
Defined benefit plan, expected future employer contributions	25,000,000
Pension Plan | U.S. | Qualified Plan
Contributions [Abstract]
Mandatory future contributions	0
Pension Plan | Non-U.S.
Components of Net Periodic Benefit Costs:
Service cost	5,000,000	7,000,000
Interest cost	29,000,000	39,000,000
Expected return on plan assets	(47,000,000)	(60,000,000)
Recognized net actuarial loss (gain)	14,000,000	10,000,000
Amortization of prior service credit	0	0
Recognized settlement loss	0	0
Recognized curtailment gain	(1,000,000)	0
Defined benefit plans	0	(4,000,000)
Defined contribution plans	5,000,000	6,000,000
Net Periodic Benefit Cost (Credit)	5,000,000	2,000,000
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive (Loss) Income:
Net actuarial loss	0	0
Amortization of net actuarial (loss) gain	(14,000,000)	(10,000,000)
Amortization of net prior service credit	0	0
Total Recognized in Other Comprehensive (Loss) Income	(14,000,000)	(10,000,000)
Total Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Loss) Income	(9,000,000)	(8,000,000)
Contributions [Abstract]
Defined benefit plan, contributions by employer	27,000,000	28,000,000	115,000,000
Defined benefit plan, expected future employer contributions	110,000,000
Retiree Health
Components of Net Periodic Benefit Costs:
Service cost	1,000,000	0
Interest cost	2,000,000	4,000,000
Expected return on plan assets	0	0
Recognized net actuarial loss (gain)	0	(1,000,000)
Amortization of prior service credit	(19,000,000)	(19,000,000)
Recognized settlement loss	0	0
Recognized curtailment gain	0	0
Defined benefit plans	(16,000,000)	(16,000,000)
Net Periodic Benefit Cost (Credit)	(16,000,000)	(16,000,000)
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive (Loss) Income:
Net actuarial loss	0	0
Amortization of net actuarial (loss) gain	0	1,000,000
Amortization of net prior service credit	19,000,000	19,000,000
Total Recognized in Other Comprehensive (Loss) Income	19,000,000	20,000,000
Total Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Loss) Income	3,000,000	4,000,000
Contributions [Abstract]
Defined benefit plan, contributions by employer	5,000,000	$ 8,000,000	$ 30,000,000
Defined benefit plan, expected future employer contributions	$ 35,000,000