Goodwill and Other Intangible Assets (Other Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Net Amount	$ 742	$ 905
Amortization expense	174	193	$ 204
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2017	146
2018	126
2019	111
2020	95
2021	80
Thereafter	184
Net Amount	$ 742	$ 905
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Period	28 months	31 months
Gross Carrying Amount	$ 70	$ 69
Accumulated Amortization	57	44
Net Amount	13	25
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Amount	$ 13	$ 25
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Period	10 years	11 years
Gross Carrying Amount	$ 1,465	$ 1,453
Accumulated Amortization	737	583
Net Amount	728	870
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Amount	$ 728	$ 870
Trade names and associated trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Period	4 months	16 months
Gross Carrying Amount	$ 80	$ 80
Accumulated Amortization	79	70
Net Amount	1	10
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Net Amount	$ 1	$ 10