Leases (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Lessee Disclosure [Abstract]
Lessee, Operating Lease, Description	we are the lessee under operating leases for real estate (office, data center, and warehouse space) and certain dedicated fiber optic lines within our infrastructure
Lessee, Operating Lease, Variable Lease Payment, Terms and Conditions	Generally, variable lease payments under these operating lease agreements relate to amounts based on changes to an index or rate (i.e. percentage change in the consumer price index)
Operating Lease, Cost	$ 37
Variable Lease, Cost	$ 1
Operating Lease, Weighted Average Remaining Lease Term	6 years 9 months 21 days
Operating Lease, Weighted Average Discount Rate, Percent	3.50%