v2.4.0.8
Pension Plans and Postretirement Benefits (Components of Benefits Expense)(Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]      
Service cost   $ 139 $ 99
Pension Benefits [Member]
     
Defined Benefit Plan Disclosure [Line Items]      
Expected return on plan assets 5.00% 5.00% 6.50%
Pension Benefits [Member] | NBCUniversal Media, LLC [Member]
     
Defined Benefit Plan Disclosure [Line Items]      
Service cost   134 99
Expected return on plan assets 5.00% 5.00%