Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt and Interest Rate Swap Arrangements (Narrative) (Details)

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Long-Term Debt and Interest Rate Swap Arrangements (Narrative) (Details) (USD $)
3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Dec. 31, 2012
Debt Instrument [Line Items]      
Line of credit facility maximum borrowing capacity $ 2,000,000,000    
Line of credit facility standby letter of credit 250,000,000    
Line of credit facility, uncommitted loan 1,000,000,000    
Debt instrument lower range of basis spread on variable rate 0.25%    
Debt instrument higher range of basis spread on variable rate 2.00%    
Line of credit facility remaining borrowing capacity 1,700,000,000    
Line of credit facility interest rate at period end 1.70%    
Debt and capital lease obligations 3,596,000,000   3,477,000,000
Loss on extinguishment of debt (41,000,000) 0  
Notional amount of interest rate derivative instruments not designated as hedging instruments     3,100,000,000
Gain on financial instruments 12,000,000 11,000,000  
Interest rate derivatives at fair value net     12,000,000
Interest rate derivative liabilities at fair value     13,000,000
Interest rate derivative assets at fair value     1,000,000
Debt weighted average interest rate 5.80%    
7.125% Senior Secured Notes due 2017
     
Debt Instrument [Line Items]      
Principal amount of tender offer 500,000,000    
Debt instrument interest rate stated percentage 7.125%    
Repurchase price of individual bonds including premium 1,039.40    
Face value of individual bonds repurchased 1,000    
Extinguishment of debt amount 124,000,000    
Extinguishment of debt, subsequent event 376,000,000    
Debt and capital lease obligations 376,000,000   500,000,000
7.5% Senior Secured Notes due 2019, net of original issue discount
     
Debt Instrument [Line Items]      
Principal amount of tender offer 250,000,000    
Debt instrument interest rate stated percentage 7.50%    
Repurchase price of individual bonds including premium 1,120    
Face value of individual bonds repurchased 1,000    
Extinguishment of debt amount 231,000,000    
Debt and capital lease obligations 760,000,000   988,000,000
7.375% Senior Secured Notes due 2020
     
Debt Instrument [Line Items]      
Debt instrument interest rate stated percentage 7.375%    
Debt and capital lease obligations 500,000,000   500,000,000
5.125% Senior Secured Notes due 2022
     
Debt Instrument [Line Items]      
Debt instrument interest rate stated percentage 5.125%    
Debt and capital lease obligations 500,000,000   500,000,000
4.375% Senior Secured Notes due 2023, net of original issue discount
     
Debt Instrument [Line Items]      
Debt instrument interest rate stated percentage 4.375%    
Debt and capital lease obligations 750,000,000   0
Debt issuance price percentage 99.968%    
5.95% Senior Secured Notes due 2043, net of original issue discount
     
Debt Instrument [Line Items]      
Debt instrument interest rate stated percentage 5.95%    
Debt and capital lease obligations $ 300,000,000   $ 0
Debt issuance price percentage 99.973%