Quarterly report pursuant to Section 13 or 15(d)

Earnings Per Share (Narrative) (Details)

v3.7.0.1
Earnings Per Share (Narrative) (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Stock repurchase plan, authorized amount $ 700,000,000   $ 700,000,000  
Aggregate shares repurchased under stock repurchase plan (in shares)     21,658,035  
Stock purchase value     $ 562,064,000  
Stock Repurchased During Period, Shares 48,943   665,095  
Stock Repurchased During Period, Value $ 2,542,000   $ 35,542,000  
Stock Options And Service-Based Restricted Stock Units [Member]        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive securities excluded from computation of earnings per share, number of shares 2,641,676 2,793,715 862,559 471,964
Performance-Based Restricted Stock Units [Member]        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive securities excluded from computation of earnings per share, number of shares 50,403 76,742 46,485 69,472