Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Debt (Junior Subordinated Notes) (Details)

v3.3.1.900
Debt (Junior Subordinated Notes) (Details)
12 Months Ended
Dec. 31, 2015
USD ($)
entity
Dec. 31, 2014
USD ($)
Debt Instrument [Line Items]    
Long-term Debt $ 29,806,843,000 $ 30,402,392,000
Subordinated Debt [Member]    
Debt Instrument [Line Items]    
Long-term Debt 1,564,045,000 $ 1,064,042,000
Junior Subordinated Notes [Member] | Subordinated Debt [Member]    
Debt Instrument [Line Items]    
Long-term Debt 500,000,000  
Face amount $ 500,000,000  
Debt, fixed interest rate 6.50%  
Applicable Margin 4.30%  
Deferral of interest payments, maximum term 5 years  
Junior Subordinated Notes [Member] | Subordinated Debt [Member] | Debt Instrument, Redemption, Option (i) [Member]    
Debt Instrument [Line Items]    
Redemption price of debt instrument, percentage 100.00%  
Junior Subordinated Notes [Member] | Subordinated Debt [Member] | Debt Instrument, Redemption, Option (iii) [Member]    
Debt Instrument [Line Items]    
Redemption price of debt instrument, percentage 100.00%  
Junior Subordinated Notes [Member] | Subordinated Debt [Member] | Debt Instrument, Redemption, Option (iv) [Member]    
Debt Instrument [Line Items]    
Redemption price of debt instrument, percentage 101.00%  
Days after occurence 60 days  
Number Of Applicable Rating Agencies | entity 2  
Annual interest rate increase 5.00%  
Revolving Credit Facility Before Issuance Of Junior Subondinated Notes [Member]    
Debt Instrument [Line Items]    
Credit facility, current borrowing capacity $ 1,000,000,000  
Revolving Credit Facility After Issuance Of Junior Subondinated Notes [Member]    
Debt Instrument [Line Items]    
Credit facility, current borrowing capacity $ 500,000,000