Debt - Term Loans Narrative (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2013	Nov. 07, 2012
Long-Term Debt Instrument [Line Items]
Debt Instrument, Covenant Description	4.00 to 1.00	4.75 to 1.00	5.00 to 1.00	6.00 to 1.00
Credit Facility Commitment Period			five-year
Unsecured Debt						$ 2,000,000,000
Net proceeds from issuance of unsecured loan			1,935,000,000
Debt Instrument Margin Rate Range, Minimum					4.50%
Base Rate Margin					0.50%
Euro Rate Margin					1.00%
Long-term Debt, Gross	13,057,000,000		12,620,000,000		13,057,000,000
Term Loan [Member]
Long-Term Debt Instrument [Line Items]
Debt Instrument Margin Rate Range, Minimum					3.50%
Term Loan [Member] | Euro Rate Floor Percentage Per Annum [Member]
Long-Term Debt Instrument [Line Items]
Debt Instrument Interest Rate Stated Percentage	1.25%				1.25%
Term Loan [Member] | Base Rate Floor Percentage Per Annum [Member]
Long-Term Debt Instrument [Line Items]
Debt Instrument Interest Rate Stated Percentage	2.25%				2.25%
Term Loan [Member] | Maximum
Long-Term Debt Instrument [Line Items]
Long-term Debt, Gross	$ 125,000,000				$ 125,000,000