v2.4.0.6
Employee Benefits, Components of Net Periodic Benefit Cost (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income [Abstract]      
Net actuarial loss (gain) $ 775 $ 1,079 $ (20)
Total recognized in other comprehensive income 631 980 (124)
Pension Benefits Qualified [Member]
      
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]      
Service cost 3 6 5
Interest cost 514 520 554
Expected return on plan assets (652) (759) (717)
Amortization of net actuarial loss 131 86 105
Amortization of prior service credit 0 0 0
Settlement loss 2 4 0
Curtailment loss (gain) 0 0 3
Net periodic benefit cost (income) (2) (143) (50)
Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income [Abstract]      
Net actuarial loss (gain) 758 1,120 (59)
Amortization of net actuarial loss (131) (86) (105)
Prior service cost (2) 0 2
Amortization of prior service cost 0 0 0
Translation adjustments 0 (1) 0
Total recognized in other comprehensive income 624 1,026 (165)
Total recognized in net periodic benefit cost and other comprehensive income 622 883 (215)
Pension Benefits Qualified [Member] | Settlement [Member]
      
Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income [Abstract]      
Settlement and Curtailment (1) (4) 0
Pension Benefits Qualified [Member] | Curtailment [Member]
      
Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income [Abstract]      
Settlement and Curtailment 0 (3) (3)
Pension Benefits Nonqualified [Member]
      
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]      
Service cost 0 1 0
Interest cost 32 34 37
Expected return on plan assets 0 0 0
Amortization of net actuarial loss 10 6 3
Amortization of prior service credit 0 0 0
Settlement loss 5 3 0
Curtailment loss (gain) 0 0 0
Net periodic benefit cost (income) 47 44 40
Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income [Abstract]      
Net actuarial loss (gain) 62 33 46
Amortization of net actuarial loss (10) (6) (3)
Prior service cost 0 0 0
Amortization of prior service cost 0 0 0
Translation adjustments 0 0 0
Total recognized in other comprehensive income 47 24 43
Total recognized in net periodic benefit cost and other comprehensive income 94 68 83
Pension Benefits Nonqualified [Member] | Settlement [Member]
      
Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income [Abstract]      
Settlement and Curtailment (5) (3) 0
Pension Benefits Nonqualified [Member] | Curtailment [Member]
      
Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income [Abstract]      
Settlement and Curtailment 0 0 0
Other benefits [Member]
      
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]      
Service cost 11 13 13
Interest cost 60 71 78
Expected return on plan assets (36) (41) (29)
Amortization of net actuarial loss 0 0 1
Amortization of prior service credit (2) (3) (4)
Settlement loss 0 0 0
Curtailment loss (gain) (3) 0 (4)
Net periodic benefit cost (income) 30 40 55
Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income [Abstract]      
Net actuarial loss (gain) (42) (74) (9)
Amortization of net actuarial loss 0 0 (1)
Prior service cost 0 0 0
Amortization of prior service cost 2 3 4
Translation adjustments 0 0 0
Total recognized in other comprehensive income (40) (71) (2)
Total recognized in net periodic benefit cost and other comprehensive income (10) (31) 53
Other benefits [Member] | Settlement [Member]
      
Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income [Abstract]      
Settlement and Curtailment 0 0 0
Other benefits [Member] | Curtailment [Member]
      
Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income [Abstract]      
Settlement and Curtailment $ 0 $ 0 $ 4