Financing (Details Textuals1) (USD $)	9 Months Ended									9 Months Ended
	Sep. 30, 2011	Sep. 30, 2011 Bridge Facility [Member] Minimum [Member]	Sep. 30, 2011 Revolving credit facility due August 29, 2016 [Member] Minimum [Member]	Sep. 30, 2011 Minimum [Member] Term facility [Member]	Sep. 30, 2011 Bridge Facility [Member] Maximum [Member]	Sep. 30, 2011 Revolving credit facility due August 29, 2016 [Member] Maximum [Member]	Sep. 30, 2011 Maximum [Member] Term facility [Member]	Sep. 30, 2011 Bridge Facility [Member]	Aug. 29, 2011 Revolving credit facility due August 29, 2016 [Member]	Sep. 30, 2011 Term facility [Member]
Line of Credit Facility [Line Items]
Margin over LIBOR interest rate		1.25%	1.10%	1.25%	1.75%	1.55%	1.75%
Margin over adjusted base rate options		0.25%	0.10%	0.25%	0.75%	0.55%	0.75%
Financing facility principal amount									$ 1,500,000,000
Bridge facility duration								1 year
Commitment fee on the unused portion of the revolving credit facility			0.15%			0.20%
Percentage margin increase								The margin will increase by 0.25% on the 90th day after the funding date of the facility and by an additional 0.25% every 90 days thereafter
Term of credit agreement with commercial bank syndicate										5 years
Commitments under the bridge facility reduction amount										4,000,000,000
Financing costs								65,000,000
Amortization period of financing costs								9 months
Expensed portion of the bridge facility financing costs								26,000,000
Financing facility unused amount								$ 14,000,000,000		$ 4,000,000,000
Financing (Textuals) [Abstract]
Description of variable rate basis	greater of LIBOR or adjusted base rate options, plus a margin