v2.4.0.6
Employee Benefit Plans - Additional Information (Detail) (USD $)
 12 Months Ended
Dec. 31, 2011
Investment
Dec. 31, 2010
Dec. 31, 2009
Dec. 31, 1995
Defined Benefit Plan Disclosure [Line Items]        
Pension settlement losses $ 21,000,000 $ 0 $ 15,000,000  
Special termination benefits 0 0 5,000,000  
Percent amortized of unamortized balance for net actuarial gain and losses 10.00%      
Measurement of the accumulated postretirement benefit obligation assumes a health care cost trend rate 7.75%      
Measurement of the accumulated postretirement benefit obligation assumes a health care cost trend rate, after decline 5.00%      
Year of measurement of the accumulated postretirement benefit obligation assumes a health care cost trend rate, after decline 2023      
Increase in fair value of debt securities 34,000,000      
Decrease in Present Value of Contract Obligation 18,000,000      
Employees maximum deposit in saving plan 75.00%      
Employees deposit in saving plan, statutory limit 16,500      
Number of investment funds in which employee can contribute 39      
Employer matching contribution up to certain percentage of eligible pay 1.25%      
Company contributions in savings plan and predecessor plans except leveraged employee stock ownership plan charged to expense 25,000,000 24,000,000 23,000,000  
Eligibility of employees to participate in leveraged employee stock ownership plan 1.00%      
Company's contribution in common stock from compensation and Benefits Trust 660,755 1,776,873 2,018,692  
Fair value of Company's contribution in common stock from compensation and Benefits Trust 84,000,000 103,000,000 94,000,000  
Company's contribution shares of company common stock from Treasury stock 475,696      
Dividends used to service debt 45,000,000 41,000,000 39,000,000  
Interest incurred on the CPSP debt 1,000,000 2,000,000 2,000,000  
Fair value of unallocated shares 59,000,000 231,000,000    
Omnibus Stock and Performance Incentive Plan life 10      
Authorized common stock for compensation plan, maximum 100,000,000      
Common stock available under incentive stock options, maximum 40,000,000      
Common stock available for awards in stock, maximum 40,000,000      
Shares available for issuance under the Plan 100,000,000      
Weighted average period of recognition of unvested options, in months 46 months      
Unrecognized compensation cost from stock options 27,000,000      
Longest weighted-average period of recognition of unvested options, in months 15 years      
Number of previously unissued common shares sold to trust 36,000,000     58,400,000
Cash received on sale of previously unissued common shares to trust       37,000,000
Promissory note received by selling of previously unissued common stock to compensation and benefits trust       952,000,000
Shares transferred out of compensation benefits trust 1,776,873      
Historical carrying value of share transfer from grantor trusts to treasury stock 610,000,000      
Stock Option [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Vest ratably options term, in year 10 years      
Weighted-average remaining contractual term of vested 3 years 11 months 12 days      
Weighted-average remaining contractual term exercisable 3 years 4 months 24 days      
Cash received from exercise of stock options 197      
Tax benefit from exercise of options 119,000,000      
Weighted average period of recognition of unvested options, in months 19 years      
Unrecognized compensation cost from stock options 16,000,000      
Stock Option [Member] | Maximum [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Weighted average period of recognition of unvested options, in months 25 years      
Stock Unit Program Period One [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Vesting period for one third of units in stock unit program 36 months      
Stock Unit Program Period Two [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Vesting period for one third of units in stock unit program 48 months      
Stock Unit Program Period Three [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Vesting period for one third of units in stock unit program 60 months      
Stock Unit Program [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Weighted average period of recognition of unvested options, in months 30 months      
Unrecognized compensation cost from stock options 188,000,000      
Longest weighted-average period of recognition of unvested options, in months 100 months      
Stock Savings Feature [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Company contributions in savings plan and predecessor plans except leveraged employee stock ownership plan charged to expense 77,000,000 92,000,000 83,000,000  
Cash contribution to the CPSP 4,000,000 0 0  
Level 3 [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of participating interest in annuity contract 144,000,000 92,000,000    
Fair value of participating interest in debt security 391,000,000 357,000,000    
Accumulated benefit obligation covered by the contract 247,000,000 265,000,000    
Equity Securities [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Target allocations for plan assets, debt securities 56.00%      
Debt Securities [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Target allocations for plan assets, debt securities 35.00%      
Real Estate [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Target allocations for plan assets, debt securities 6.00%      
Other Investment [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Target allocations for plan assets, debt securities 3.00%      
Tax Qualified Pension Plan [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Tax-qualified pension plans with projected benefit obligations in excess of plan assets 8,481,000,000 7,661,000,000    
Tax-qualified pension plans with accumulated benefit obligation in excess of plan assets 7,377,000,000 6,718,000,000    
Tax-qualified pension plans with fair value of plan assets in excess of plan assets 6,098,000,000 5,706,000,000    
Unfunded Non Qualified Key Employee Pension Plan [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Tax-qualified pension plans with projected benefit obligations in excess of plan assets 499,000,000 479,000,000    
Tax-qualified pension plans with accumulated benefit obligation in excess of plan assets 374,000,000 407,000,000    
Domestic Qualified And Nonqualified Pension And Postretirement Benefit Plans [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Expected contribution to qualified and non qualified pension and post retirement benefit 690,000,000      
International Qualified And Nonqualified Pension And Postretirement Benefit Plans [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Expected contribution to qualified and non qualified pension and post retirement benefit 235,000,000      
Int'l (Pension Benefits) [Member]
        
Defined Benefit Plan Disclosure [Line Items]        
Company contributions in savings plan and predecessor plans except leveraged employee stock ownership plan charged to expense $ 56,000,000 $ 52,000,000 $ 51,000,000