Regulatory Assets, Liabilities, And Balancing Accounts (Current Regulatory Balancing Accounts, Net) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Regulatory Balancing Accounts Receivable [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	$ 2,204	$ 2,266
Regulatory Balancing Accounts Receivable [Member] | Electric distribution [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	672	344
Regulatory Balancing Accounts Receivable [Member] | Utility Generation [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	392	261
Regulatory Balancing Accounts Receivable [Member] | Gas distribution [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	504	566
Regulatory Balancing Accounts Receivable [Member] | Energy Procurement [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	308	608
Regulatory Balancing Accounts Receivable [Member] | Public Purpose Programs [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	82	109
Regulatory Balancing Accounts Receivable [Member] | Other Current Balancing Accounts [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	246	378
Regulatory Balancing Accounts Payable [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	876	1,090
Regulatory Balancing Accounts Payable [Member] | Energy Procurement [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	173	188
Regulatory Balancing Accounts Payable [Member] | Public Purpose Programs [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	177	154
Regulatory Balancing Accounts Payable [Member] | Other Current Balancing Accounts [Member]
Regulatory Assets [Line Items]
Total regulatory balancing accounts, net	$ 526	$ 748