Related Party (Debt Agreements) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Related Party [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 2,200,000,000		$ 2,200,000,000
Interest Expense	10,000,000	10,000,000	20,000,000	20,000,000
Current Principle Amount	1,725,000,000		1,725,000,000
Opening Principle Amount					1,783,000,000
Prudential Insurance Debt, Borrowing Date	2010-12-20		2010-12-20
Prudential Insurance Debt, Maturity Date	2015-12-21		2015-12-21
Prudential Financial Debt, Borrowing Date	2010-11-15		2010-11-15
Prudential Financial Debt, Maturity Date	2015-11-13		2015-11-13
Prudential Financial Debt, Repayment Date	2011-12-15		2011-12-15
Prudential Financial June Term Out Debt, Borrowing Date	2011-06-20		2011-06-20
Prudential Financial June Term Out Debt, Close Maturity Date	2012-06-19		2012-06-19
Prudential Financial June Term Out Debt, Far Maturity Date	2016-06-19		2016-06-19
Prudential Financial December Term Out Debt, Borrowing Date 2	2011-12-15		2011-12-15
Prudential Financial December Term Out Debt, Borrowing Date 2	2011-12-16		2011-12-16
Prudential Financial December Term Out Debt, Close Maturity Date	2012-12-16		2012-12-16
Prudential Financial December Term Out Debt, Far Maturity Date	2016-12-16		2016-12-16
Washington Street June Term Out Debt, Borrowing Date	2012-06-20		2012-06-20
Washington Street June Term Out Debt, Close Maturity Date	2014-06-15		2014-06-15
Washington Street June Term Out Debt, Far Maturity Date	2017-06-15		2017-06-15
Prudential Financial Loan 1 [Member]
Related Party [Line Items]
Borrowing Date	2010-11-15		2010-11-15
Current Principle Amount	66,000,000		66,000,000
Opening Principle Amount					66,000,000
Interest Rate			3.01%
Maturity Date	2015-11-13		2015-11-13
Prudential Financial Loan 2 [Member]
Related Party [Line Items]
Borrowing Date	2011-06-20		2011-06-20
Current Principle Amount	150,000,000		150,000,000
Opening Principle Amount					200,000,000
Interest Rate Near			1.64%
Interest Rate Far			3.17%
Maturity Date Near	2012-06-19		2012-06-19
Maturity Date Far	2016-06-19		2016-06-19
Prudential Financial Loan 3 [Member]
Related Party [Line Items]
Borrowing Date	2011-12-15		2011-12-15
Current Principle Amount	212,000,000		212,000,000
Opening Principle Amount					212,000,000
Interest Rate Near			2.65%
Interest Rate Far			3.61%
Maturity Date Near	2013-12-16		2013-12-16
Maturity Date Far	2016-12-15		2016-12-15
Prudential Financial Loan 4 [Member]
Related Party [Line Items]
Borrowing Date	2011-12-16		2011-12-16
Current Principle Amount	44,000,000		44,000,000
Opening Principle Amount					44,000,000
Interest Rate Near			2.65%
Interest Rate Far			3.61%
Maturity Date Near	2013-12-16		2013-12-16
Maturity Date Far	2016-12-16		2016-12-16
Prudential Financial Loan 5 [Member]
Related Party [Line Items]
Borrowing Date	2012-12-20		2012-12-20
Opening Principle Amount	267,000,000		267,000,000		267,000,000
Interest Rate			1.37%
Maturity Date	2015-12-15		2015-12-15
Prudential Insurance Loan 1 [Member]
Related Party [Line Items]
Borrowing Date	2010-12-20		2010-12-20
Current Principle Amount	204,000,000		204,000,000
Opening Principle Amount					204,000,000
Interest Rate			3.47%
Maturity Date	2015-12-21		2015-12-21
Washington Street Loan 1 [Member]
Related Party [Line Items]
Borrowing Date	2012-06-20		2012-06-20
Current Principle Amount	316,000,000		316,000,000
Opening Principle Amount					395,000,000
Interest Rate Near			1.15%
Interest Rate Far			3.02%
Maturity Date Near	2013-06-15		2013-06-15
Maturity Date Far	2017-06-15		2017-06-15
Washington Street Loan 2 [Member]
Related Party [Line Items]
Borrowing Date	2012-12-17		2012-12-17
Current Principle Amount	330,000,000		330,000,000
Opening Principle Amount					330,000,000
Interest Rate Near			0.95%
Interest Rate Far			1.87%
Maturity Date Near	2013-12-17		2013-12-17
Maturity Date Far	2017-12-17		2017-12-17
Washington Street Loan 3 [Member]
Related Party [Line Items]
Borrowing Date	2012-12-17		2012-12-17
Current Principle Amount	65,000,000		65,000,000
Opening Principle Amount					65,000,000
Interest Rate Near			0.95%
Interest Rate Far			1.87%
Maturity Date Near	2013-12-17		2013-12-17
Maturity Date Far	2017-12-17		2017-12-17
Pru Funding Loan 1 [Member]
Related Party [Line Items]
Borrowing Date	2013-06-21		2013-06-21
Current Principle Amount	15,000,000		15,000,000
Opening Principle Amount	0		0
Interest Rate			0.20%
Maturity Date	2013-07-03		2013-07-03
Pru Funding Loan 2 [Member]
Related Party [Line Items]
Borrowing Date	2013-06-20		2013-06-20
Current Principle Amount	53,000,000		53,000,000
Opening Principle Amount	0		0
Interest Rate			0.20%
Maturity Date	2013-07-11		2013-07-11
Pru Funding Loan 3 [Member]
Related Party [Line Items]
Borrowing Date	2013-06-25		2013-06-25
Current Principle Amount	3,000,000		3,000,000
Opening Principle Amount	$ 0		$ 0
Interest Rate			0.20%
Maturity Date	2013-07-10		2013-07-10