Revenue Recognition Accounting Policy (Details 3) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred Revenue	$ 413	$ 415
Less than 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred Revenue, Revenue Expected to be Recognized	65
1 - 2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred Revenue, Revenue Expected to be Recognized	60
2 - 3 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred Revenue, Revenue Expected to be Recognized	56
3 - 4 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred Revenue, Revenue Expected to be Recognized	50
4 - 5 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred Revenue, Revenue Expected to be Recognized	44
Thereafter
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred Revenue, Revenue Expected to be Recognized	$ 138