LEASES - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2019	Dec. 31, 2020	Dec. 31, 2019
Operating lease cost		$ 20	$ 21
Short-term lease cost		22	25
Variable lease cost		8	4
Amortization of right-of-use assets - finance		2	1
Total lease cost		52	51
Operating cash flows for operating leases		19	21
Financing cash flows for finance leases		2	1
Right-of-use assets obtained in exchange for lease obligations:	$ 99	48	105
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability		3	0
Operating lease assets		123	89
Finance lease assets		15	12
Finance lease amortization		(5,824)	(5,878)
Total lease assets		130
Operating lease liabilities - current		19	16
Finance Lease, Liability, Current		2	1
Operating lease liabilities - noncurrent		105	74
Finance Lease, Liability, Noncurrent		5	5
Total lease liabilities		$ 131	$ 96
Operating Lease, Weighted Average Remaining Lease Term		7 years 6 months	6 years 3 months 18 days
Finance Lease, Weighted Average Remaining Lease Term		3 years 4 months 24 days	4 years 6 months
Operating Lease, Weighted Average Discount Rate, Percent		3.28%	4.13%
Finance Lease, Weighted Average Discount Rate, Percent		3.62%	4.22%
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year		$ 23
Finance Lease, Liability, Payments, Due Next Twelve Months		2
Lessee, Operating Lease, Liability, Payments, Due Year Two		22
Finance Lease, Liability, Payments, Due Year Two		2
Lessee, Operating Lease, Liability, Payments, Due Year Three		20
Finance Lease, Liability, Payments, Due Year Three		2
Lessee, Operating Lease, Liability, Payments, Due Year Four		19
Finance Lease, Liability, Payments, Due Year Four		1
Lessee, Operating Lease, Liability, Payments, Due Year Five		18
Finance Lease, Liability, Payments, Due Year Five		0
Lessee, Operating Lease, Liability, Payments, Due after Year Five		38
Finance Lease, Liability, Payments, Due after Year Five		0
Lessee, Operating Lease, Liability, Payments, Due		140
Finance Lease, Liability, Payment, Due		7
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		16
Finance Lease, Liability, Undiscounted Excess Amount		0
Operating lease, liability		124
Finance Lease, Liability		7
Lessee, Additional Leases Not yet Commenced, Assumptions and Judgment, Amount		$ 1
Lessee, Additional Leases Not yet Commenced, Term of Contract		2 years
finance leases [Member]
Finance lease amortization		$ (8)	$ (6)
Total lease assets			$ 95
Maximum [Member]
Lessee, Operating and Finance Leases, Remaining Lease Term		20 years