RETIREMENT BENEFITS Retirement Benefits - Obligations and Funded Status (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Service Cost		$ 1	$ 1	$ 0
Interest cost		3	2	1
Fair value of plan assets at beginning of period		141
Fair value of plan assets at end of period		169	141
Other Postretirement Benefits Plan [Member]
Benefit obligation at beginning of period		78	25
Defined Benefit Plan, Service Cost		1	1
Interest cost		3	2
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment		0	56
Actuarial gain		12	(3)
Benefit obligation at end of period		91	78	25
Fair value of plan assets at beginning of period		141	143
Return on plan assets and other		23	(7)
Employer contributions		8	8
Defined Benefit Plan, Benefit Obligation, Benefits Paid		3	3
Fair value of plan assets at end of period		169	141	$ 143
Amount overfunded at end of period (1)	[1]	78	63
Net actuarial gain		(5)	(2)
Prior service cost		37	61
Amounts recognized in accumulated other comprehensive income (pre-tax basis) consist of:		$ 32	$ 59

[1] Recorded as a non-current asset in the consolidated balance sheets.