RETIREMENT AND OTHER BENEFIT PROGRAMS - Net Periodic Benefit Cost - Continuing Operations (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net periodic benefit cost
Settlement charge	$ 755	$ (755)	$ (1)	$ (2)
Pension benefits
Net periodic benefit cost
Service cost		74	87	91
Interest cost		172	178	180
Expected return on plan assets		(264)	(303)	(291)
Amortization of net losses and other deferred amounts		58	94	163
Other		0	0	(2)
Net periodic benefit cost		795	57	143
OPEB
Net periodic benefit cost
Service cost		1	1	1
Interest cost		8	7	7
Amortization of net losses and prior service credit		(27)	(25)	(26)
Net periodic benefit cost		$ (18)	$ (17)	$ (18)