Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 9
Operating Lease, Weighted Average Discount Rate, Percent	5.00%
Short-term Lease, Cost	$ 2
Operating Lease, Cost	12	$ 10
Operating lease assets	40	44
Finance Lease, Right-of-Use Asset	0	1
Leases of Lessee Disclosure [Text Block]	40	45
Operating Lease, Liability, Current	8	8
Finance Lease, Liability, Current	0	0
Non-current operating lease liabilities	32	36
Finance Lease, Liability, Noncurrent	0	1
Total lease liabilities	40	45
Finance Lease, Right-of-Use Asset, Amortization	0	0
Finance Lease, Interest Expense	0	0
Total lease costs	12	10
Operating Lease, Payments	9	9
Variable Lease, Cost		31
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 4	47
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability		$ 1
Finance Lease, Weighted Average Discount Rate, Percent	4.00%
Operating Lease, Weighted Average Remaining Lease Term	12 years
Finance Lease, Weighted Average Remaining Lease Term	2 years
Finance Lease, Liability, Payments, Remainder of Fiscal Year	$ 0
Lease, Liability, Payments, Remainder of Fiscal Year	9
Lessee, Operating Lease, Liability, Payments, Due Year Two	7
Finance Lease, Liability, Payments, Due Year Two	0
Lease, Liability, Payments, Due Year Two	7
Lessee, Operating Lease, Liability, Payments, Due Year Three	4
Finance Lease, Liability, Payments, Due Year Three	0
Lease, Liability, Payments, Due Year Three	4
Lessee, Operating Lease, Liability, Payments, Due Year Four	3
Finance Lease, Liability, Payments, Due Year Four	0
Lease, Liability, Payments, Due Year Four	3
Lessee, Operating Lease, Liability, Payments, Due Year Five	2
Finance Lease, Liability, Payments, Due Year Five	0
Lease, Liability, Payments, Due Year Five	2
Lessee, Operating Lease, Liability, Payments, Due after Year Five	27
Finance Lease, Liability, Payments, Due after Year Five	0
Lease, Liability, Payments, Due After Year Five	27
Lessee, Operating Lease, Liability, Payments, Due	52
Finance Lease, Liability, Payment, Due	0
Lease, Liability, Payments Due	52
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(12)
Finance Lease, Liability, Undiscounted Excess Amount	0
Lease, liability, undiscounted excess amount	(12)
Operating Lease, Liability	40
Finance Lease, Liability	$ 0
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent