Goodwill and Other Intangible Assets (Other Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Net Amount	$ 905	$ 1,106
Amortization expense	193	204	$ 178
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2016	173
2017	144
2018	124
2019	110
2020	94
Thereafter	260
Net Amount	$ 905	$ 1,106
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Period	31 months	40 months
Gross Carrying Amount	$ 69	$ 70
Accumulated Amortization	44	31
Net Amount	25	39
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Amount	$ 25	$ 39
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Period	11 years	12 years
Gross Carrying Amount	$ 1,453	$ 1,496
Accumulated Amortization	583	451
Net Amount	870	1,045
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Amount	$ 870	$ 1,045
Trade names and associated trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Period	16 months	28 months
Gross Carrying Amount	$ 80	$ 80
Accumulated Amortization	70	58
Net Amount	10	22
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Amount	$ 10	$ 22