Significant Accounting Policies (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012 percent	Jun. 30, 2011 percent	Jun. 30, 2012 percent	Jun. 30, 2011 percent	Dec. 31, 2011
Significant Accounting Policies [Line Items]
Effective Income Tax Rate, Continuing Operations	32.00%	14.00%	32.00%	17.00%
Current Income Tax Expense (Benefit)				$ 88
Unrecognized Tax Benefits	3		3		4
Unrecognized Tax Benefits, Decreases Resulting from Settlements with Taxing Authorities			30
Collateral Already Posted, Aggregate Fair Value	11		11
Cash Collateral Paid or Received for Derivative Assets or Derivative Liabilities	0		0
Cash Collateral Paid	6		6
Cash Collateral Received	$ 17		$ 17
Minimum [Member]
Significant Accounting Policies [Line Items]
Minimum Finite-Lived Intangible Asset, Useful Life	3		3
Maximum [Member]
Significant Accounting Policies [Line Items]
Maximum Finite Lived Intangible Assets Useful Life	20		20