Employee Benefit Plans (Details) $ in Millions		3 Months Ended		6 Months Ended
	Apr. 03, 2020 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, number of plan participants	3,400
Defined benefit plan, benefit obligation, (increase) decrease due to remeasurement	$ 2,400
Contributions - Defined benefit plans		$ 34	$ 33	$ 42	$ 37
Contributions - Defined contribution plans		227	117	440	252
Liability, Defined Benefit Pension Plan, Noncurrent		14,972		14,972		$ 2,487
Non-service pension (income) cost		(237)	(200)	(405)	(392)
Total net periodic benefit (income) cost				(223)	(244)
Fair Value, Recurring [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Marketable securities held in trusts		758		758		0
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Liability, Defined Benefit Pension Plan, Noncurrent		13,774		13,774		1,770
Service cost		142	74	179	146
Interest cost		452	321	705	642
Expected return on plan assets		(814)	(568)	(1,335)	(1,136)
Amortization of prior service cost (credit)		13	4	26	9
Recognized actuarial net loss (gain)		83	49	169	98
Net settlement and curtailment loss		27	0	27	8
Non-service pension (income) cost		(239)	(194)	(408)	(379)
Total net periodic benefit (income) cost		(97)	(120)	(229)	(233)
Pension Plan [Member] | UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions - Defined contribution plans				77
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Liability, Defined Benefit Pension Plan, Noncurrent		1,069		1,069		696
Service cost		2	1	3	2
Interest cost		10	8	16	16
Expected return on plan assets		(4)	0	(5)	(1)
Amortization of prior service cost (credit)		(1)	(11)	(2)	(22)
Recognized actuarial net loss (gain)		(3)	(3)	(6)	(6)
Net settlement and curtailment loss		0	0	0	0
Non-service pension (income) cost		2	(6)	3	(13)
Total net periodic benefit (income) cost		4	$ (5)	6	$ (11)
Other pension and PRB related items
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Liability, Defined Benefit Pension Plan, Noncurrent		$ 129		$ 129		$ 21