Fair Value (Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 256	$ 65
Trading securities	52	38
Total assets	308	103
Contingent Value Right (CVR)	9
CVR-related legal liability	291
Fair value of interest rate swap agreements	57	88
Total liabilities	357	88
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	127	65
Trading securities	52	38
Total assets	179	103
Contingent Value Right (CVR)	9
Total liabilities	9
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	129
Total assets	129
Fair value of interest rate swap agreements	57	88
Total liabilities	57	88
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
CVR-related legal liability	291
Total liabilities	$ 291