Revenues (Unrecognized Revenues Under Contract) (Details) $ in Millions	Jun. 30, 2020 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Unrecognized revenue	$ 6,790
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-07-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Unrecognized revenue	$ 1,950
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction period	6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Unrecognized revenue	$ 2,550
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Unrecognized revenue	$ 1,630
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Unrecognized revenue	$ 661
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction period