XML 65 R50.htm IDEA: XBRL DOCUMENT v3.20.4
Summary Of Significant Accounting Policies (Narrative) (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
USD ($)
shares
Dec. 31, 2019
USD ($)
shares
Dec. 31, 2018
USD ($)
shares
Dec. 31, 2005
Item
Dec. 31, 2017
USD ($)
Summary Of Significant Accounting Policies [Line Items]          
Minimum percent of prepaid reinsurance premiums for any foreign reinsurers that were collateralized 10.00%        
Derivatives, number of indices | Item       2  
Anti-dilutive options | shares 0 0 0    
Change in beginning balance due to adoption of ASU $ 9,726,176 $ 9,132,925 $ 7,860,797    
Operating lease right of use assets $ 149,125 $ 161,435 $ 69,869    
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] Other assets Other assets Other assets    
Operating lease liabilities $ 165,292 $ 169,909 $ 77,270    
Operating Lease, Liability, Statement of Financial Position [Extensible List] Other liabilities Other liabilities Other liabilities    
Accumulated Other Comprehensive Income [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Change in beginning balance due to adoption of ASU $ 534,899 $ 28,152 $ (462,557)   $ (160,891)
Accumulated Other Comprehensive Income [Member] | Cumulative Effect Period Of Adoption Adjustment [Member] | Accounting Standards Update 2016-01 [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Change in beginning balance due to adoption of ASU     (1,201)
Retained Earnings [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Change in beginning balance due to adoption of ASU $ 10,567,452 10,306,571 9,531,433   9,657,412
Retained Earnings [Member] | Cumulative Effect Period Of Adoption Adjustment [Member] | Accounting Standards Update 2016-13 [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Change in beginning balance due to adoption of ASU   (4,214)  
Retained Earnings [Member] | Cumulative Effect Period Of Adoption Adjustment [Member] | Accounting Standards Update 2016-01 [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Change in beginning balance due to adoption of ASU     $ 1,201
Minimum [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Options expiration date Feb. 24, 2021        
Maximum [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Options expiration date Sep. 19, 2022