Stock-Based Compensation (Stock Options Outstanding and Exercisable by Exercise Price) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2015	Jul. 16, 2014
Stock Options Outstanding And Exercisable By Exercise Price Range [Line Items]
Number of stock options outstanding	11,305,035
Number of stock options exercisable	6,199,611
Weighted average remaining contractual life of outstanding stock options (years)	4 years 10 months 24 days
Intrinsic value of stock options outstanding	$ 122
Weighted average remaining contractual life of exercisable stock options (years)	3 years 11 months 9 days
Intrinsic value of stock options exercisable	$ 108
Share price	$ 47.13	$ 60.85
$5 to $9.99 [Member]
Stock Options Outstanding And Exercisable By Exercise Price Range [Line Items]
Exercise price range, lower range limit	5
Exercise price range, upper range limit	$ 9.99
Number of stock options outstanding	676,135
Number of stock options exercisable	676,135
Stock options outstanding, weighted average exercise price	$ 5.25
Stock options exercisable, weighted average exercise price	$ 5.25
Weighted average remaining contractual life of outstanding stock options (years)	1 year 2 months 27 days
$10 to $19.99 [Member]
Stock Options Outstanding And Exercisable By Exercise Price Range [Line Items]
Exercise price range, lower range limit	$ 10
Exercise price range, upper range limit	$ 19.99
Number of stock options outstanding	488,744
Number of stock options exercisable	488,744
Stock options outstanding, weighted average exercise price	$ 14.10
Stock options exercisable, weighted average exercise price	$ 14.10
Weighted average remaining contractual life of outstanding stock options (years)	2 years 5 months 1 day
$20 to $29.99 [Member]
Stock Options Outstanding And Exercisable By Exercise Price Range [Line Items]
Exercise price range, lower range limit	$ 20
Exercise price range, upper range limit	$ 29.99
Number of stock options outstanding	2,744,846
Number of stock options exercisable	2,322,791
Stock options outstanding, weighted average exercise price	$ 27.83
Stock options exercisable, weighted average exercise price	$ 27.54
Weighted average remaining contractual life of outstanding stock options (years)	3 years 10 months 10 days
$30 to $39.99 [Member]
Stock Options Outstanding And Exercisable By Exercise Price Range [Line Items]
Exercise price range, lower range limit	$ 30
Exercise price range, upper range limit	$ 39.99
Number of stock options outstanding	1,339,775
Number of stock options exercisable	1,168,110
Stock options outstanding, weighted average exercise price	$ 34.08
Stock options exercisable, weighted average exercise price	$ 34.03
Weighted average remaining contractual life of outstanding stock options (years)	4 years 8 months 9 days
$40 to $49.99 [Member]
Stock Options Outstanding And Exercisable By Exercise Price Range [Line Items]
Exercise price range, lower range limit	$ 40
Exercise price range, upper range limit	$ 49.99
Number of stock options outstanding	2,219,630
Number of stock options exercisable	971,946
Stock options outstanding, weighted average exercise price	$ 44.28
Stock options exercisable, weighted average exercise price	$ 44.36
Weighted average remaining contractual life of outstanding stock options (years)	5 years 2 months 1 day
$50 to $59.99 [Member]
Stock Options Outstanding And Exercisable By Exercise Price Range [Line Items]
Exercise price range, lower range limit	$ 50
Exercise price range, upper range limit	$ 59.99
Number of stock options outstanding	1,817,150
Number of stock options exercisable	44,672
Stock options outstanding, weighted average exercise price	$ 59.54
Stock options exercisable, weighted average exercise price	$ 59.58
Weighted average remaining contractual life of outstanding stock options (years)	7 years 4 days
$60 to $69.99 [Member]
Stock Options Outstanding And Exercisable By Exercise Price Range [Line Items]
Exercise price range, lower range limit	$ 60
Exercise price range, upper range limit	$ 69.99
Number of stock options outstanding	2,018,755
Number of stock options exercisable	527,213
Stock options outstanding, weighted average exercise price	$ 65.86
Stock options exercisable, weighted average exercise price	$ 65.91
Weighted average remaining contractual life of outstanding stock options (years)	6 years 26 days

No definition available.

Name:	cbs_StockOptionsOutstandingAndExercisableByExercisePriceRangeLineItems
Namespace Prefix:	cbs_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(iii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbs_Range5To999Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbs_Range10To1999Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbs_Range20To2999Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbs_Range30To3999Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbs_Range40To4999Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbs_Range50to5999Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbs_Range60To6999Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: