BASIS OF PRESENTATION - Other Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Other intangible assets
Gross Carrying Amount	$ 2,741	$ 2,694
Accumulated Amortization	(1,130)	(1,092)
Net Book Value	1,611	1,602
Capitalized software costs
Other intangible assets
Gross Carrying Amount	1,657	1,616
Accumulated Amortization	(948)	(912)
Net Book Value	709	704
Trade names
Other intangible assets
Gross Carrying Amount	102	102
Accumulated Amortization	0	0
Net Book Value	102	102
Contracts
Other intangible assets
Gross Carrying Amount	877	869
Accumulated Amortization	(98)	(94)
Net Book Value	779	775
Other
Other intangible assets
Gross Carrying Amount	105	107
Accumulated Amortization	(84)	(86)
Net Book Value	$ 21	$ 21