Share-Based Payments (Summary Of Compensation Costs Recognized In The Consolidated Statements of Operations) (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | |||
| Tax benefits related to compensation cost | $ (13,000,000) | $ (13,000,000) | $ (23,000,000) |
| Allocated Share-based Compensation Expense, Net of Tax | 38,000,000 | 37,000,000 | 39,000,000 |
| Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation | (12,000,000) | ||
| Restricted Stock Awards [Member] | |||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | |||
| Allocated Share-Based Compensation Expense | $ 51,000,000 | $ 50,000,000 | $ 62,000,000 |