v3.6.0.2
Income Taxes (Federal Statutory) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Income Taxes [Line Items]      
Federal tax at statutory rate $ 5,024 $ 4,680 $ 4,363
State income taxes, net of federal benefit 373 326 329
Foreign income taxes, net of federal credit 65 13 0
Nontaxable income attributable to noncontrolling interests (128) (69) (62)
Other adjustments (67) (79) (114)
Income tax expense 5,308 4,959 3,873
Uncertain And Effectively Settled Tax Positions, Net [Member]      
Income Taxes [Line Items]      
Other adjustments 24 15 (408)
Accrued Interest On Uncertain And Effectively Settled Tax Positions Net [Member]      
Income Taxes [Line Items]      
Other adjustments $ 17 $ 73 $ (235)