Intangible Assets (Narrative) (Details) (Customer Relationships [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Reduction in carrying value and accumulated amortization of fully amortized intangible assets	$ 107

Amount of fully amortized finite-lived intangible assets

No definition available.

Name:	s_ReductionInCarryingValueAndAccumulatedAmortizationOfFullyAmortizedIntangibleAssets
Namespace Prefix:	s_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration