v2.4.0.8
Shareholders' Equity (Details 3) (USD $)
In Millions, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2012
Sep. 30, 2012
Jun. 30, 2012
Mar. 31, 2012
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Significant reclassifications from accumulated other comprehensive income to net income                      
Total amortization, before income taxes                 $ 1,664 $ 866 $ (5,438)
Income tax (benefit) expense                 (258) (50) (324)
Total amortization, net of income taxes 233 546 307 321 456 (381) (304) 10 1,407 (219) (5,754)
Defined benefit pension plans | Amount Reclassified from Accumulated Other Comprehensive Income
                     
Significant reclassifications from accumulated other comprehensive income to net income                      
Actuarial losses                 48 45 26
Prior service costs                   (1) (1)
Settlements and curtailments                 1 3  
Total amortization, before income taxes                 49 47 25
Income tax (benefit) expense                 (4) (5) 13
Total amortization, net of income taxes                 45 42 38
Defined benefit pension plans | Amount Reclassified from Accumulated Other Comprehensive Income | Operating and maintenance costs
                     
Significant reclassifications from accumulated other comprehensive income to net income                      
Total amortization, net of income taxes                 37 31 17
Defined benefit pension plans | Amount Reclassified from Accumulated Other Comprehensive Income | General and administrative costs
                     
Significant reclassifications from accumulated other comprehensive income to net income                      
Total amortization, net of income taxes                 $ 12 $ 16 $ 8