Fair Value (Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 264	$ 65
Trading securities	52	38
Total assets	316	103
Contingent Value Right (CVR)	18
CVR-related legal liability	284
Fair value of interest rate swap agreements	74	88
Total liabilities	376	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	130	65
Trading securities	52	38
Total assets	182	103
Contingent Value Right (CVR)	18
Total liabilities	18
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	134
Total assets	134
Fair value of interest rate swap agreements	74	88
Total liabilities	74	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	284
Total liabilities	$ 284