Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies - Litigation and Regulatory Matters (Details)

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Commitments and Contingencies - Litigation and Regulatory Matters (Details)
 1 Months Ended 3 Months Ended
Oct. 31, 2016
lawsuit
Mar. 31, 2018
USD ($)
Mar. 31, 2017
USD ($)
Loss Contingencies [Line Items]      
Litigation settlement expense   $ 116,000,000 $ 274,000,000
Minimum      
Loss Contingencies [Line Items]      
Estimated range of possible loss   0  
Maximum      
Loss Contingencies [Line Items]      
Estimated range of possible loss   $ 1,200,000,000  
Waldrup and Williams, et al      
Loss Contingencies [Line Items]      
Number of lawsuits | lawsuit 2