Equity-Indexed Compensation Plans (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended			80 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 AAP Management Units	Mar. 31, 2014 AAP Management Units
Reserved for Future Grants
Reserved for future grants outstanding, beginning balance (in units)			3.5
Units granted (in units)			(0.4)
Reserved for future grants outstanding, ending balance (in units)			3.1	3.1
Outstanding
Outstanding at the beginning of the period (in units)			48.6
Units granted (in units)			0.4
Outstanding at the ending of the period (in units)			49.0	49.0
Outstanding Units Earned
Outstanding Units Earned, beginning balance (in units)			47.0
Units earned (in units)			0.3
Outstanding Units Earned, end balance (in units)			47.3	47.3
Grant Date Fair Value of Outstanding AAP Management Units:
Grant Date Fair Value of Outstanding AAP Management Units, beginning balance			$ 51
Units granted			11
Grant Date Fair Value of Outstanding AAP Management Units, ending balance			62	62
Equity-indexed compensation expense	$ 34	$ 51	$ 1	$ 50