Employee Benefit Plans (Narrative) (Details)	12 Months Ended
Dec. 31, 2022 USD ($) decimal shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Minimum Years Of Service For Eligible Employees Of Postretirement Plans	1 year
Minimum Number Of Hours Worked By Employees \| decimal	1,000
Automatic Cash Contribution	2.00%	2.00%	2.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 22,000,000		$ 19,000,000
Defined Contribution Plan, Cost	$ 67,000,000	$ 63,000,000	62,000,000
Total Company Common Stock Shares Held Under Defined Contribution Plan \| shares	16,000,000	17,000,000
Dividends Earned By Defined Contribution Plan	$ 12,000,000	$ 11,000,000	$ 12,000,000
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	5.00%	5.00%	5.00%
Qualified Plan [Member] \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation	$ 1,500,000,000	$ 2,100,000,000
Expected long-term rate of return on plan assets for net periodic benefit cost, next fiscal year	6.37%
Number of shares held in plan assets relating to company's common stock (whole number) \| shares	2,855,618
Approximate percentage of company's common stock shares held in plan assets	3.00%
Qualified Plan [Member] \| Equity Securities [Member] \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation For Defined Benefit Plan Equity Securities	35.00%
Qualified Plan [Member] \| Fixed Income Securities [Member] \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation For Defined Benefit Plan Equity Securities	59.00%
Qualified Plan [Member] \| Other Security Investments [Member] \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation For Defined Benefit Plan Equity Securities	6.00%
Qualified Plan [Member] \| Defined Benefit Plan, Equity Securities, Common Stock, Employer, Related Party [Member] \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Market Value Of Companys Common Stock Held In Plan Assets	$ 62,000,000
Nonqualified Plan [Member] \| Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation	$ 127,000,000	$ 155,000,000

2% cash 401(k) Contribution to eligible employees regardless of whether or not they were contributing to the 401(k) plan. To receive the contribution, employees must not be actively accruing a benefit in the Region's pension plan and must be employed at the end of the year

No definition available.